CN105140280A - High-voltage multi-heterojunction device with normally-off channels - Google Patents

Abstract

The present invention relates to a heterojunction device with a new enhancement mechanism of power electronics technology, and in particular to a high-voltage multi-heterojunction device with a normally-off channel. The multi-heterojunction normally-off channel device of the present invention mainly uses the The third semiconductor layer, the fourth semiconductor layer, the fifth semiconductor layer, and the sixth semiconductor layer form a multi-heterojunction, with a non-planar structure under the gate, and the polarization direction of the non-planar heterojunction channel is the same as that of the third semiconductor layer. , The material growth directions of the fourth semiconductor layer, the fifth semiconductor layer and the sixth semiconductor layer have a certain angle to realize the discontinuity of the two-dimensional electron gas (2DEG) at the heterojunction interface, that is, a very closed electric current is formed between the source and the drain. connection, and finally realize the multi-heterojunction normally-off channel device. The beneficial effect of the invention is that the multi-heterojunction normally-off channel device can work stably in a high-temperature and high-field environment, the layout and process are easy to realize, and the threshold voltage of the normally-off channel is easy to control.

Description

A high-voltage multi-heterojunction device with a normally-off channel

technical field

The invention relates to semiconductor technology, in particular to the realization principle and preparation technology of multi-heterojunction normally-off channels.

Background technique

The III-V semiconductor materials in the third-generation semiconductors have the characteristics of large band gap, high electron saturation velocity, high breakdown electric field, strong thermal conductivity and corrosion resistance, such as GaN, AlN, etc. In terms of electronic devices, III-V Group V materials are more suitable than silicon for making semiconductor devices with high temperature resistance, high frequency, high field and high power.

When preparing electronic devices with III-V heterojunction structures, due to the strong two-dimensional electron gas in the III-V heterojunction structures, such as AlGaN/GaN heterojunction high electron mobility transistors (HEMTs) , most of them are depletion-type devices, and it is not easy to realize the electronic devices of enhanced III-V heterojunction, but in many cases in high-frequency devices, power switching devices and digital circuits, enhanced devices are needed , so for the enhanced III-V heterojunction.

The main methods to realize enhanced III-V heterojunction high electron mobility transistors (HEMTs) are: (1) p-type cap layer enhanced HEMTs; (2) concave barrier layer enhanced HEMTs; (3) double Barrier layer enhanced HEMTs; (4) insulated gate heterojunction transistors; (5) fluorine ion implantation enhanced HEMTs, etc.

The Chinese patent with the publication number CN103715086A proposes an enhanced AlGaN/GaN single heterojunction device, which utilizes at least one non-planar single heterojunction structure, so that the polarization direction of the III-V group material and the material growth The crystal orientation has a certain angle, thereby weakening the electric field that can generate two-dimensional electron gas (2DEG) or two-dimensional hole gas (2DHG), thereby realizing an enhanced device. However, because the growth of III-V growth materials is relatively complicated, it is difficult to achieve control by making grooves, protrusions and steps from the substrate, and then growing non-planar single heterojunction channels by epitaxy. In the actual process, multi-heterojunction devices are relatively easy to realize and flexible.

Contents of the invention

As mentioned in the background technology, by making grooves, bumps and steps in the substrate, and then by epitaxial growth, the shape of the substrate is transferred to the channel layer, so that the gate region of the channel layer is formed The non-planar structure uses the non-polar surface and semi-polar surface of the non-planar structure to realize the interruption of the two-dimensional electron gas, thereby realizing the enhanced device. However, from the current process technology, the process of transferring the shape of the substrate to the channel layer through the deposition and growth of several layers is very complicated and difficult to control, and the non-polar or semi-polar surface of the non-planar single heterojunction way is more difficult to implement.

Therefore, the present invention discloses an enhanced device. The principle of pinching off two-dimensional electron gas or two-dimensional hole gas of the enhanced device is based on the characteristic that III-V semiconductor is a kind of polar semiconductor. For example, in the wurtzite structure III-V group compound, in the crystal direction [0001] or Even if the AlGaN/GaN heterojunction is not doped, a very high two-dimensional electron gas (2DEG) will be generated on the GaN surface of the heterojunction. As shown in Figure 1, piezoelectric polarization σ _i'j' = C _i'j'k'm' ε k'm _' , where C _i'j'k'm' is the elastic stiffness coefficient, ε _{k'm '} is the gauge factor. When forming a heterojunction, the piezoelectric polarization σ _i'j' can be obtained from the values of C _i'j'k'm' and ε k'm _' in the crystal direction, as shown in Figure 1a As shown, when taking the (10-11)-plane, a-plane and r-plane crystal orientations, different piezoelectric polarization electric fields can be obtained. In a multi-heterojunction structure, the piezoelectric polarization electric field is The two-dimensional electron gas (2DEG) at the junction interface has a regulating effect. The piezoelectric field is strong, and the two-dimensional electron gas is relatively easy to accumulate. The piezoelectric field is weak, and the ability to accumulate two-dimensional electron gas is weakened; and within GaN along [0001] and The spontaneous polarization electric field in the crystal direction is the strongest, and when the AlGaN barrier layer is relatively thin, the two-dimensional electron gas at the AlGaN/GaN heterojunction interface is mainly caused by the spontaneous polarization electric field, so in the crystal direction[0001] and The two-dimensional electron gas (2DEG) generated by the heterojunction on is the strongest, and along the crystal direction and crystal direction [0001] and When there is an AlGaN/GaN heterojunction with a certain angle, such as the (10-11)-plane, a-plane and r-plane in Figure 1b, the spontaneous polarization electric field will be weakened, and even when along the crystal direction and the crystal direction[ 0001] and When the heterojunction is vertical, there is no spontaneous polarization electric field; the present invention forms a multi-heterojunction through a growth plane different from the c-plane, and adjusts the heterojunction interface by adjusting the material growth crystal direction of the non-planar multi-heterojunction The piezoelectric polarization electric field and the spontaneous polarization electric field at , make the conduction band of the quantum well at the interface above the Fermi level, so it is difficult to form a two-dimensional electron gas at the interface of the non-planar multi-heterojunction channel.

In order to achieve the above object, the technical solution provided by the present invention is as follows: a high-voltage multi-heterojunction device with a normally-off channel, including a first semiconductor substrate layer 201, a second semiconductor buffer layer 202, The third semiconductor layer 203, the fourth semiconductor layer 204, and the fifth semiconductor layer 205; the upper surfaces of both ends of the fourth semiconductor layer 204 are respectively provided with a first ohmic contact 101 and a second ohmic contact 103; the fifth semiconductor layer There is a metal electrode 102 on the layer 205; the third semiconductor layer 203 and the fourth semiconductor layer 204 form a first heterojunction at the contact interface, and the fourth semiconductor layer 204 and the fifth semiconductor layer 205 form a first heterojunction at the contact interface. Two heterojunctions; it is characterized in that there is a non-planar heterojunction under the metal electrode 102 that interrupts the two-dimensional electron gas channel directly below it.

Further, as shown in FIG. 2, the non-planar heterojunction is formed by the fifth semiconductor layer 205 recessed through the fourth semiconductor layer 204 and connected to the upper surface of the third semiconductor layer 203; the fifth semiconductor layer A groove is formed between 205 and the metal electrode 102 , and the metal electrode 102 is filled in the groove; there is a sixth semiconductor layer 206 between the fifth semiconductor layer 205 and the metal electrode 102 .

Furthermore, both ends of the sixth semiconductor layer 206 are respectively connected to the first ohmic contact 101 and the second ohmic contact 103; there is a seventh semiconductor layer 207 between the sixth semiconductor layer 206 and the metal electrode 102; Both ends of the seventh semiconductor layer 207 are respectively connected to the first ohmic contact 101 and the second ohmic contact 103 .

Still further, the first semiconductor substrate layer 201 is one of sapphire, silicon and silicon carbide; the second semiconductor 202 is one of SiC, AlN, GaN, and AlGaN; the third semiconductor Layer 203, the fourth semiconductor layer 204, the fifth semiconductor layer 205, the sixth semiconductor layer 206 and the seventh semiconductor layer 207 are III-V compounds; the electrode materials of the first ohmic contact 101 and the second ohmic contact 103 It is one or more combinations of gold, silver, aluminum, titanium, platinum and indium; the material of the metal electrode 102 is titanium, gold, nickel, platinum, nuclei, tungsten, silver, aluminum, titanium, molybdenum and One or more combinations of indium.

A high-voltage multi-heterojunction device with a normally-off channel, comprising a first semiconductor substrate layer 201, a second semiconductor buffer layer 202, a third semiconductor layer 203, and a fourth semiconductor layer 204 arranged sequentially from bottom to top; The upper surfaces of both ends of the third semiconductor layer 203 are respectively provided with a first ohmic contact 101 and a second ohmic contact 103; the fourth semiconductor layer 204 has a metal electrode 102; the third semiconductor layer 203 and the fourth semiconductor layer Layer 204 forms a first heterojunction at the contact interface; it is characterized in that there is a non-planar heterojunction under the metal electrode 102 that interrupts the two-dimensional electron gas channel directly below.

Further, the fourth type semiconductor layer 204 is composed of a bent surface and a horizontal plane; a non-planar heterojunction is formed at the bent surface of the fourth semiconductor layer 204; the bent surface of the fourth semiconductor layer 204 is located at directly below the metal electrode 102 .

Further, the bending surface of the fourth semiconductor layer 204 is bent upward, and the cross-sectional shape between the lower surface at the bending surface of the fourth semiconductor layer 204 and the upper surface of the third semiconductor layer 203 is trapezoidal , the width of the lower base of the trapezoid is greater than the width of the upper base, and the third semiconductor layer 203 is filled in the trapezoid and connected with the lower surface of the bending surface of the fourth semiconductor layer 204; the fourth semiconductor layer 204 is connected with the metal There is also a fifth semiconductor layer 205 between the electrodes 102, and the fifth semiconductor layer 205 completely covers the upper surface of the fourth semiconductor layer 204; the metal electrode 102 covers the bending surface portion of the fifth semiconductor layer 205 surface.

Further, the bending surface of the fourth semiconductor layer 204 is bent upward, and the cross-sectional shape between the lower surface at the bending surface of the fourth semiconductor layer 204 and the upper surface of the third semiconductor layer 203 is trapezoidal , the width of the lower base of the trapezoid is greater than the width of the upper base; the trapezoid is filled with an eighth semiconductor layer 208, and the connection between the eighth semiconductor layer 208 and the fourth semiconductor layer forms a second heterojunction; The metal electrode 102 covers the upper surface of the bent surface of the fourth semiconductor layer 204 .

Further, the bending surface of the fourth semiconductor layer 204 is bent upward, and the cross-sectional shape between the lower surface at the bending surface of the fourth semiconductor layer 204 and the upper surface of the third semiconductor layer 203 is trapezoidal , the width of the lower base of the trapezoid is greater than the width of the upper base; the third semiconductor layer 203 is filled in the trapezoid; the metal electrode 102 is composed of a first vertical plane, a second vertical plane and a plane; the metal electrode 102 The plane of the metal electrode 102 is parallel to the horizontal plane of the fourth semiconductor layer 204; the plane of the metal electrode 102 is connected with the first vertical plane of the metal electrode 102 and the second vertical plane of the metal electrode 102 to form an inverted U-shaped structure; the metal electrode 102 The plane of the metal electrode 102 is perpendicular to the first vertical plane of the metal electrode 102 and the second vertical plane of the metal electrode 102; The surface is connected, and its upper surface is connected with the lower surface of one end of the plane of the metal electrode 102; the lower surface of the second vertical plane of the metal electrode 102 is connected with the upper surface of the horizontal plane on the other side of the bending surface of the fourth semiconductor layer 204, and the upper surface The surface is connected to the lower surface of the other end of the plane of the metal electrode 102; there is a tenth semiconductor layer 210 between the plane of the metal electrode 102 and the upper bottom surface of the bending surface of the fourth semiconductor layer 204; the tenth semiconductor layer 210, There is a ninth semiconductor layer 209 between the vertical surface of the metal electrode 102 , the horizontal surface of the metal electrode 102 and the bent surface of the fourth semiconductor layer 204 .

Further, the bending surface of the fourth semiconductor layer 204 is formed by the fourth semiconductor layer 204 being concave, and the cross-sectional shape between the upper surface of the bending place of the fourth semiconductor layer 204 and the horizontal plane of the fourth semiconductor layer 204 is Trapezoid, the width of the lower base of the trapezoid is greater than the width of the upper base; the metal electrode 102 is composed of a plane and a vertical plane, and the plane lower surface of the metal electrode 102 is on the same plane as the upper surface of the fourth semiconductor layer 204, and the metal electrode 102 The vertical surface of the electrode 102 is arranged in the trapezoidal bending surface; the plane of the metal electrode 102 is perpendicular to the vertical surface of the metal electrode 102 to form a T-shaped structure; the vertical surface of the metal electrode 102 is aligned with the upper surface of the fourth semiconductor layer 204 There is a tenth semiconductor layer 210 in between, and a ninth semiconductor layer 209 between it and the sides of the trapezoidal bending surface.

Furthermore, the first semiconductor substrate layer 201 is one of sapphire, silicon and silicon carbide; the second semiconductor 202 is one of SiC, AlN, GaN, and AlGaN; the third semiconductor Layer 203, the fourth semiconductor layer 204, the eighth semiconductor layer 208, the ninth semiconductor layer 209 and the tenth semiconductor layer 210 are III-V compounds; the electrode materials of the first ohmic contact 101 and the second ohmic contact 103 It is one or more combinations of gold, silver, aluminum, titanium, platinum and indium, and the material of the metal electrode 102 is titanium, gold, nickel, platinum, nuclei, tungsten, silver, aluminum, titanium, molybdenum and indium One or more combinations of them.

Since this enhanced device is fabricated with a non-planar multi-heterojunction structure formed on the metal electrode region on the channel layer by etching, deposition, etc., the process is relatively easy to implement, and the formed non-planar multi-heterojunction Knots are more flexible.

Description of drawings

Fig. 1 is the lattice structure schematic diagram of III-V group compound;

Wherein Fig. 1 (a) is the wurtzite structure figure of III-V compound, and Fig. 1 (b) is the lattice structure figure of the wurtzite structure of III-V compound;

2 is a schematic structural view of Embodiment 1 of a high-voltage multi-heterojunction device with a normally-off channel of the present invention;

3 is a schematic structural view of Embodiment 2 of a high-voltage multi-heterojunction device with a normally-off channel of the present invention;

Fig. 4 is a schematic structural view of Embodiment 3 of a high-voltage multi-heterojunction device with a normally-off channel of the present invention;

5 is a schematic structural view of Embodiment 4 of a high-voltage multi-heterojunction device with a normally-off channel of the present invention;

Fig. 6 is a schematic structural view of Embodiment 5 of a high-voltage multi-heterojunction device with a normally-off channel of the present invention;

7 is a schematic structural view of Embodiment 6 of a high-voltage multi-heterojunction device with a normally-off channel of the present invention;

8 is a schematic diagram of a high-voltage multi-heterojunction device manufacturing process with a normally-off channel of the present invention after depositing the second type of semiconductor, the third semiconductor layer and the fourth semiconductor layer on the substrate;

9 is a schematic diagram of the structure of a high-voltage multi-heterojunction device with a normally-off channel in the manufacturing process of the present invention after etching the fourth semiconductor layer material on the device to form grooves;

Fig. 10 is a schematic structural view of a high-voltage multi-heterojunction device with a normally-off channel in the manufacturing process of the present invention after sequentially depositing materials for the fifth semiconductor layer, the sixth semiconductor layer, and the seventh semiconductor layer on the fourth semiconductor layer ;

Fig. 11 is a schematic diagram of the structure after making ohmic contacts at both ends of the fourth semiconductor layer in the manufacturing process of a high-voltage multi-heterojunction device with a normally-off channel according to the present invention;

FIG. 12 is a schematic diagram of a high-voltage multi-heterojunction device with a normally-off channel of the present invention on which metal electrodes are deposited on the seventh semiconductor layer.

Detailed ways

Example 1

A high-voltage heterojunction device with a normally-off channel in this example, as shown in FIG. 2 , includes a first semiconductor substrate layer 201, a second semiconductor buffer layer 202, a third semiconductor layer 203, The fourth semiconductor layer 204, the fifth semiconductor layer 205, and the sixth semiconductor layer 206; the two ends of the fourth semiconductor layer 204 are respectively provided with a first ohmic contact 101 and a second ohmic contact 103; the sixth semiconductor layer 206 has a metal electrode 102, and the metal electrode 102 is between the first ohmic contact 101 and the second ohmic contact 103; the junction of the third semiconductor layer 203 and the fourth semiconductor layer 204 forms a first heterojunction, and the The junction of the fourth semiconductor layer 204 and the fifth semiconductor layer 205 forms a second heterojunction, the junction of the fifth semiconductor layer 205 and the third semiconductor layer 203 forms a third heterojunction, the fifth semiconductor layer 205 and The junction of the sixth semiconductor layer 206 forms a fourth heterojunction; the self-polarization electric field of the heterojunction between the fifth semiconductor layer 205 and the sixth semiconductor layer 206 and the heterojunction between the fourth semiconductor layer 204 and the fifth semiconductor layer The self-polarization electric field of is opposite and forms a non-planar multi-heterojunction under the metal electrode 102 .

The first semiconductor substrate layer 201 is one of sapphire, silicon and silicon carbide; the second semiconductor buffer layer 202 is mainly one of SiC, AlN, GaN, and AlGaN; the third semiconductor layer 203 , the fourth semiconductor layer 204, the fifth semiconductor layer 205, and the sixth semiconductor layer 206 are mainly GaN, InN, AlGaN, InGaN, InAlGaN or AlN. The electrode materials of the first ohmic contact 101 and the second ohmic contact 103 include gold. , silver, aluminum, titanium, platinum, or one or more combinations of indium; the material of the metal electrode 102 includes titanium, gold, nickel, platinum, nuclei, tungsten, silver, aluminum, titanium, molybdenum, or indium One or more combinations of them.

The principle of a high-voltage multi-heterojunction device with a normally-off channel in Embodiment 1 is through the third semiconductor layer 203, the fourth semiconductor layer 204, the fifth semiconductor layer 205, and the sixth semiconductor layer under the metal electrode 102. Layer 206 forms a non-planar trapezoidal groove multi-heterojunction structure; the upper surface and lower surface of the groove and the semiconductor in the device except the protrusion are along the crystal direction [0001] or the crystal direction The fourth semiconductor layer 204, the fifth semiconductor layer 205, and the sixth semiconductor layer 206 on the side of the groove formed by the bent segments are deposited and grown along the crystal direction [0001] or the crystal direction Deposited at an angle; along [0001] or When the III-V group semiconductor grown in the same direction forms a heterojunction, the polarization electric field at the interface of the heterojunction is the strongest, and the fifth semiconductor layer 205 on the lower surface of the trapezoidal groove is connected to the third semiconductor layer 203 to form a third heterojunction A two-dimensional electron gas (2DEG) channel is easily formed at the junction; on the side of the groove, because the growth directions of the fourth semiconductor layer 204, the fifth semiconductor layer 205, and the sixth semiconductor layer 206 are in line with [0001] or are not parallel, so the polarization electric field of the second heterojunction formed by connecting the fourth semiconductor layer 204 and the fifth semiconductor layer 205 and the fourth heterojunction formed by connecting the fifth semiconductor layer 205 and the sixth semiconductor layer 206 is relatively weak, And the direction of the self-polarization electric field of the fourth heterojunction of the fifth semiconductor layer 205 and the sixth semiconductor layer 206 is opposite to the direction of the self-polarization electric field of the second heterojunction of the fourth semiconductor layer 204 and the fifth semiconductor layer 205, The self-polarization electric field of the first heterojunction of the fourth semiconductor layer 204 and the third semiconductor layer 203 is further weakened, so that the two-dimensional electron gas (2DEG) at the cross section of the first heterojunction on the side of the groove is depleted.

Example 2

A high-voltage multi-heterojunction device with a normally-off channel in this example, as shown in FIG. , the fourth semiconductor layer 204, the fifth semiconductor layer 205, the sixth semiconductor layer 206, and the seventh semiconductor layer 207; the two ends of the fourth semiconductor layer 204 are respectively provided with a first ohmic contact 101 and a second ohmic contact 103; The seventh semiconductor layer 207 has a metal electrode 102, and the metal electrode 102 is between the first ohmic contact 101 and the second ohmic contact 103; the connection between the third semiconductor layer 203 and the fourth semiconductor layer 204 forms the first A heterojunction, the junction of the fourth semiconductor layer 204 and the fifth semiconductor layer 205 forms a second heterojunction, the junction of the fifth semiconductor layer 205 and the third semiconductor layer 203 forms a third heterojunction, and the junction of the fifth semiconductor layer 205 and the third semiconductor layer 203 forms a third heterojunction. The junction of the fifth semiconductor layer 205 and the sixth semiconductor layer 206 forms a fourth heterojunction, the junction of the sixth semiconductor layer 206 and the seventh semiconductor layer 207 forms a fifth heterojunction, and the junction of the fifth semiconductor layer 205 and the sixth semiconductor layer The self-polarization electric field of the fourth heterojunction of 206 and the fifth heterojunction of the sixth semiconductor layer 206 and the seventh semiconductor layer 207 and the self-polarization electric field of the second heterojunction of the fourth semiconductor layer 204 and the fifth semiconductor layer 205 The polarizing electric fields are opposite and a non-planar multiple heterojunction is formed under the metal electrode 102 .

The first semiconductor substrate layer 201 is one of sapphire, silicon and silicon carbide; the second semiconductor buffer layer 202 is mainly one of SiC, AlN, GaN, and AlGaN; the third semiconductor layer 203 , the fourth semiconductor layer 204, the fifth semiconductor layer 205, the sixth semiconductor layer 206 and the seventh semiconductor layer 207 are mainly GaN, InN, AlGaN, InGaN, InAlGaN or AlN; the first ohmic contact 101 and the second ohmic The electrode material of the contact 103 includes one or more combinations of gold, silver, aluminum, titanium, platinum, and indium; the material of the metal electrode 102 includes titanium, gold, nickel, platinum, nolium, tungsten, silver, One or more combinations of aluminum, titanium, molybdenum and indium.

The principle of Embodiment 2 is to form a non-planar trapezoidal groove through the third semiconductor layer 203, the fourth semiconductor layer 204, the fifth semiconductor layer 205, the sixth semiconductor layer 206 and the seventh semiconductor layer 207 under the metal electrode 102. Multi-heterojunction structure; the upper and lower surfaces of the groove and the semiconductor in the device except the groove are along the crystal direction [0001] or the crystal direction Deposition and growth, the fourth semiconductor layer 204, the fifth semiconductor layer 205, the sixth semiconductor layer 206, and the seventh semiconductor layer 207 on the side of the groove composed of bent segments are along the crystal direction [0001] or the crystal direction Deposited at an angle; along [0001] or When the III-V group semiconductors grown in the same direction form a heterojunction, the polarization electric field at the interface of the heterojunction is the strongest, so the fifth semiconductor layer 205 on the lower surface of the trapezoidal groove is connected to the third semiconductor layer 203 to form the third semiconductor layer 205. The heterojunction is easy to form a two-dimensional electron gas (2DEG) channel; on the groove side, due to the growth direction of the fourth semiconductor layer 204, the fifth semiconductor layer 205, the sixth semiconductor layer 206 and the seventh semiconductor layer here with [0001] or are not parallel, so the second heterojunction formed at the junction of the fourth semiconductor layer 204 and the fifth semiconductor layer 205, the fourth heterojunction formed at the junction of the fifth semiconductor layer 205 and the sixth semiconductor layer 206, and the sixth semiconductor layer The polarization electric field of the fifth heterojunction formed at the connection between 206 and the seventh semiconductor layer 207 is relatively weak, and the fourth heterojunction formed by the fifth semiconductor layer 205 and the sixth semiconductor layer 206 and the sixth semiconductor layer 206 and the seventh semiconductor layer The direction of the self-polarization electric field of the fifth heterojunction formed by the semiconductor layer 207 is opposite to the direction of the self-polarization electric field of the second heterojunction formed by the fourth semiconductor layer 204 and the fifth semiconductor layer 205, further the second heterojunction The self-polarization electric field depletes the two-dimensional electron gas (2DEG) at the second heterojunction interface on the side of the groove.

Example 3

A high-voltage multi-heterojunction device with a normally-off channel in this example, as shown in FIG. , the fourth semiconductor layer 204, the fifth semiconductor layer 205; the two ends of the third semiconductor layer 203 are respectively provided with a first ohmic contact 101 and a second ohmic contact 103; the fifth semiconductor layer 205 has a metal electrode 102, the metal electrode 102 is between the first ohmic contact 101 and the second ohmic contact 103; the junction of the third semiconductor layer 203 and the fourth semiconductor layer 204 forms a first heterojunction, and the fourth semiconductor layer 204 The junction with the fifth semiconductor layer 205 forms a second heterojunction, and the self-polarization electric field of the heterojunction between the fourth semiconductor layer 204 and the fifth semiconductor layer 205 is the same as that of the heterojunction between the third semiconductor layer 203 and the fourth semiconductor layer 204. The self-polarization electric field of the junction is opposite and a non-planar multi-heterojunction is formed under the metal electrode 102 .

The first semiconductor substrate layer 201 is one of sapphire, silicon and silicon carbide; the second semiconductor buffer layer 202 is mainly one of SiC, AlN, GaN, and AlGaN; the third semiconductor layer 203 , the fourth semiconductor layer 204, and the fifth semiconductor layer 205 are mainly GaN, InN, AlGaN, InGaN, InAlGaN or AlN; the electrode materials of the first ohmic contact 101 and the second ohmic contact 103 include gold, silver, aluminum, One or more combinations of titanium, platinum and indium; the material of the metal electrode 102 includes one or more of titanium, gold, nickel, platinum, nuclei, tungsten, silver, aluminum, titanium, molybdenum and indium kind of combination.

The principle of Embodiment 3 is to form a non-planar trapezoidal raised double heterojunction structure through the third semiconductor layer 203, the fourth semiconductor layer 204, and the fifth semiconductor layer 205 below the metal electrode 102; the raised upper surface and The bottom surface and the semiconductor in the device except the bumps are along the crystal direction [0001] or the crystal direction Deposited and grown, the fourth semiconductor layer 204 and the fifth semiconductor layer 205 on the convex side composed of bent segments are aligned with the crystal direction [0001] or the crystal direction Deposited at an angle; along [0001] or When the III-V group semiconductor grown in the same direction forms a heterojunction, the polarization electric field at the interface of the heterojunction is the strongest, so the fourth semiconductor layer 204 on the upper surface of the trapezoidal protrusion is connected to the third semiconductor layer 203 to form the first Two-dimensional electron gas (2DEG) channels are easily formed at the heterojunction; on the side of the protrusion, because the growth directions of the third semiconductor layer 203, the fourth semiconductor layer 204, and the fifth semiconductor layer 205 are in line with [0001] or are not parallel, so the spontaneous polarization of the first heterojunction formed by the connection of the fourth semiconductor layer 204 and the third semiconductor layer 203 at the side and the second heterojunction formed by the connection of the fifth semiconductor layer 205 and the fourth semiconductor layer 204 The electric field is weak, and the direction of the self-polarization electric field of the second heterojunction of the fifth semiconductor layer 205 and the fourth semiconductor layer 204 is the same as the self-polarization of the first heterojunction of the fourth semiconductor layer 204 and the third semiconductor layer 203 The direction of the electric field is opposite, further weakening the self-polarization electric field of the first heterojunction of the fourth semiconductor layer 204 and the third semiconductor layer 203, so that the two-dimensional electron gas (2DEG) at the first heterojunction on the side of the protrusion is depleted .

Example 4

A high-voltage heterojunction device with a normally-off channel in this example, as shown in FIG. 5 , includes a first semiconductor substrate layer 201, a second semiconductor buffer layer 202, a third semiconductor layer 203, The fourth semiconductor layer 204, the eighth semiconductor layer 208; the two ends of the third semiconductor layer 203 are respectively provided with the first ohmic contact 101 and the second ohmic contact 103; the third semiconductor layer 203 and the fourth semiconductor layer 204 The first heterojunction is formed at the junction of the fourth semiconductor layer 204. The bent section of the fourth semiconductor layer 204 is that the fourth semiconductor layer 204 protrudes upwards to form a trapezoidal bent section. The width of the bottom edge; the trapezoidal bending section is filled with an eighth semiconductor layer 208, and the connection between the eighth semiconductor layer and the upper bottom edge of the fourth semiconductor layer forms a second heterojunction; the metal electrode 102 covers A non-planar heterojunction is formed on the outer side surface of the trapezoidal bending section and the upper surface of the upper bottom edge; below the metal electrode 102 .

The first semiconductor substrate layer 201 is one of sapphire, silicon and silicon carbide; the second semiconductor buffer layer 202 is mainly one of SiC, AlN, GaN, and AlGaN; the third semiconductor layer 203 , the fourth semiconductor layer 204, and the eighth semiconductor layer 208 are mainly GaN, InN, AlGaN, InGaN, InAlGaN or AlN; further, the electrode materials of the first ohmic contact 101 and the second ohmic contact 103 include gold, silver , aluminum, titanium, platinum, and indium; the material of the metal electrode 102 includes one of titanium, gold, nickel, platinum, nuclei, tungsten, silver, aluminum, titanium, molybdenum, and indium one or more combinations.

The principle of a high-voltage heterojunction device with multiple heterojunctions in Embodiment 4 is that an eighth semiconductor layer 208 is deposited and grown between the third semiconductor layer 203 and the fourth semiconductor layer 204 under the metal electrode 102, And the third semiconductor layer 203, the fourth semiconductor layer 204, and the eighth semiconductor layer 208 form a non-planar trapezoidal raised heterojunction structure. To [0001] or crystal direction Deposited and grown, the fourth semiconductor layer 204 and the eighth semiconductor layer 208 on the convex side composed of bent segments are along the crystal direction [0001] or the crystal direction Deposited and grown at a certain angle; the eighth semiconductor layer 208 and the third semiconductor layer 203 on the lower surface of the trapezoidal protrusion form a third heterojunction, because the thickness of the eighth semiconductor layer 208 is relatively thick, so that the first semiconductor layer here Two-dimensional electron gas (2DEG) cannot be formed at the interface of the three heterojunctions; the second heterojunction between the fourth semiconductor layer 204 and the eighth semiconductor layer 208 on the upper surface of the trapezoidal protrusion is along [0001] or In the III-V semiconductor heterojunction grown in the direction of growth, the polarization electric field at the heterojunction interface is the strongest, so it is easy to form a two-dimensional electron gas (2DEG) channel at the second heterojunction interface on the upper surface of the protrusion; on the contrary , the second heterojunction on the side of the protrusion, because the growth direction of the third semiconductor layer 204 and the eighth semiconductor layer 208 on the side is the same as [0001] or are not parallel, so the polarization electric field of multiple heterojunctions on the side of the protrusion is weaker, making it difficult to form 2DEG at the interface of the second heterojunction on the side of the protrusion.

Example 5

A high-voltage heterojunction device with a normally-off channel in this example, as shown in FIG. 6 , includes a first semiconductor substrate layer 201, a second semiconductor buffer layer 202, a third semiconductor layer 203, The fourth semiconductor layer 204, the ninth semiconductor layer 209, and the tenth type semiconductor 210; the two ends of the third semiconductor layer 203 are respectively provided with a first ohmic contact 101 and a second ohmic contact 103; the ninth semiconductor layer 209 and the tenth semiconductor layer 210 have a metal electrode 102, and the metal electrode 102 is between the first ohmic contact 101 and the second ohmic contact 103; the junction of the third semiconductor layer 203 and the fourth semiconductor layer 204 forms a first A heterojunction, the junction of the ninth semiconductor layer 209 and the fourth semiconductor layer 204 forms a second heterojunction, and the junction of the tenth semiconductor layer 210 and the fourth semiconductor layer 204 forms a third heterojunction; The self-polarization electric field of the second heterojunction between the ninth semiconductor layer 209 and the fourth semiconductor layer 204 and the third heterojunction between the tenth semiconductor layer 210 and the fourth semiconductor layer 204 and the fourth semiconductor layer 204 and the third semiconductor layer The self-polarizing electric field of the first heterojunction of layer 203 is opposite and forms a non-planar multiple heterojunction under metal electrode 102 .

The first semiconductor substrate layer 201 is one of sapphire, silicon and silicon carbide; the second semiconductor buffer layer 202 is mainly one of SiC, AlN, GaN, and AlGaN; the third semiconductor layer 203 , the fourth semiconductor layer 204, the ninth semiconductor layer 209 and the tenth semiconductor layer 210 are mainly GaN, InN, AlGaN, InGaN, InAlGaN or AlN; the electrode materials of the first ohmic contact 101 and the second ohmic contact 103 include Gold, silver, aluminum, titanium, platinum, or indium; the material of the metal electrode 102 includes titanium, gold, nickel, platinum, nuclei, tungsten, silver, aluminum, titanium, molybdenum, or indium.

A high-voltage multi-heterojunction device with a normally-off channel in Embodiment 5 is a non-planar trapezoidal raised heterojunction structure formed by the third semiconductor layer 203 and the fourth semiconductor layer 204 under the metal electrode 102, And the ninth semiconductor layer 209 and the tenth semiconductor layer 210 are respectively deposited and grown on the bending section and the horizontal section of the fourth semiconductor layer 204 on the raised upper surface; The semiconductor is along the crystal direction [0001] or the crystal direction The third semiconductor layer 203, the fourth semiconductor layer 204, and the ninth semiconductor layer 209 on the convex side formed by the bent segments are deposited and grown along the crystal direction [0001] or the crystal direction Deposited and grown at a certain angle; the fourth type semiconductor 204 on the upper surface of the trapezoidal protrusion is connected to the third semiconductor layer 203 to form a first heterojunction structure, along [0001] or When the III-V group semiconductor grown in the direction of the heterojunction forms a heterojunction, the polarization electric field at the heterojunction interface is the strongest, so it is easy to form a two-dimensional electron gas (2DEG) channel at the third heterojunction; on the side of the protrusion, Since the growth directions of the third semiconductor layer 203, the fourth semiconductor layer 204, and the ninth semiconductor layer 209 are the same as [0001] or are not parallel, the polarization electric field of the second heterojunction between the ninth semiconductor layer 209 and the fourth semiconductor layer 204 and the first heterojunction between the fourth semiconductor layer 204 and the third semiconductor layer 203 is relatively weak, and the second heterojunction The direction of the self-polarization electric field of the junction is opposite to the direction of the self-polarization electric field of the first heterojunction, further weakening the self-polarization electric field of the first heterojunction of the fourth semiconductor layer 204 and the third semiconductor layer 203, so that the protrusion The two-dimensional electron gas (2DEG) on the upper surface of the third semiconductor layer 203 at the side is depleted.

Example 6

A high-voltage multi-heterojunction device with a normally-off channel in this example, as shown in FIG. , the fourth semiconductor layer 204, the ninth semiconductor layer 209, and the tenth semiconductor layer 210; the two ends of the third semiconductor layer 203 are respectively provided with a first ohmic contact 101 and a second ohmic contact 103; the ninth semiconductor layer There is a metal electrode 102 on the layer 209 and the tenth semiconductor layer 210, and the metal electrode 102 is between the first ohmic contact 101 and the second ohmic contact 103; the junction of the third semiconductor layer 203 and the fourth semiconductor layer 204 forms the first A heterojunction, the junction of the ninth semiconductor layer 209 and the fourth semiconductor layer 204 forms a second heterojunction, and the junction of the tenth semiconductor layer 210 and the fourth semiconductor layer 204 forms a third heterojunction The self-polarization electric field of the second heterojunction of the ninth semiconductor layer 209 and the sixth semiconductor layer 204 and the third heterojunction of the tenth semiconductor layer 210 and the fourth semiconductor layer 204 and the fourth semiconductor layer 204 and the third The self-polarization electric field of the first heterojunction of the semiconductor layer 203 is opposite and forms non-planar multiple heterojunctions under the metal electrode 102 .

The first semiconductor substrate layer 201 is one of sapphire, silicon and silicon carbide; the second semiconductor buffer layer 202 is mainly one of SiC, AlN, GaN, and AlGaN; the third semiconductor layer 203 , the fourth semiconductor layer 204, the ninth semiconductor layer 209 and the tenth semiconductor layer 210 are mainly GaN, InN, AlGaN, InGaN, InAlGaN or AlN; further, the first ohmic contact 101 and the second ohmic contact 103 The electrode material includes one or more combinations of gold, silver, aluminum, titanium, platinum, and indium; the material of the metal electrode 102 includes titanium, gold, nickel, platinum, nuclei, tungsten, silver, aluminum, titanium, One or more combinations of molybdenum and indium.

The principle of the fifth embodiment is to form a non-planar trapezoidal groove heterojunction structure through the third semiconductor layer 203 and the fourth semiconductor layer 204 under the metal electrode 102, and the fourth semiconductor layer 204 on the upper surface of the groove Deposit and grow the ninth semiconductor layer 209 and the tenth semiconductor layer 210 respectively in the bending section and the horizontal section; the upper surface and the lower surface of the groove and the semiconductor in the device except the groove are along the crystal direction [0001] or the crystal direction The third semiconductor layer 203, the fourth semiconductor layer 204, and the ninth semiconductor layer 209 on the side of the groove formed by the bent segments are grown along the crystal direction [0001] or the crystal direction Deposited and grown at a certain angle; the fifth semiconductor layer 204 on the lower surface of the trapezoidal groove is connected to the third semiconductor layer 203 to form a first heterojunction structure, along [0001] or When the III-V semiconductors grown in the same direction form a heterojunction, the polarization electric field at the heterojunction interface is the strongest, so it is easy to form a two-dimensional electron gas (2DEG) channel at the first heterojunction on the lower surface of the groove; Groove side, because the growth direction of the third semiconductor layer 203, the fourth semiconductor layer 204, the ninth semiconductor layer 209 and [0001] or are not parallel, the polarization electric field of the second heterojunction between the ninth semiconductor layer 209 and the fourth semiconductor layer 204 on the side and the first heterojunction between the fourth semiconductor layer 204 and the third semiconductor layer 203 is relatively weak, and the ninth The direction of the self-polarization electric field of the second heterojunction of the semiconductor layer 209 and the fourth semiconductor layer 204 is opposite to the direction of the self-polarization electric field of the first heterojunction of the fourth semiconductor layer 204 and the third semiconductor layer 203, further weakening The self-polarization electric field of the first heterojunction between the fourth semiconductor layer 204 and the third semiconductor layer 203 depletes the two-dimensional electron gas (2DEG) on the upper surface of the third semiconductor layer 203 at the side of the groove.

In order to better understand the structure of the present invention, the present invention provides a manufacturing process of a heterojunction high-voltage device with a normally-off channel:

Step 1: Deposit AlN buffer layer and GaN, Al _x Ga _1-x N in sequence on the silicon substrate by organic chemical deposition method, and the value of x is 0 to 1; Al _x Ga _1-x N and GaN are connected Form an Al _x Ga _1-x N/GaN heterojunction at , as shown in Figure 8, then use a pulsed laser to deposit a Si ₃ N ₄ film of about 500nm as a mask, and etch a groove on the Al _x Ga _1-x N window, as shown in Figure 9;

The second step: Deposit Al _y Ga ₁ on Al _x Ga _1-x N and GaN at the bottom of the groove by organic chemical vapor deposition (MOCVD), atomic layer epitaxy (ALD) or molecular beam epitaxy (MBE) _-y N, Al _z Ga _1-z N, Al _w Ga _1-w N layers, where the values of y, z, and w range from 0 to 1; and Al _x is formed at the junction of Aly Ga _{1-y N} and GaN Ga _1-x N/GaN heterojunction, _{AlyGa 1 -y /} Al _x Ga _{1 -x N} heterojunction, Al _z Ga Al _z Ga _1-z N/ _Aly Ga _1-y N heterojunction is formed at the junction of 1- _z N and Al _y Ga ₁ -y N, and the junction of Al _w Ga _1-w N and Al _z Ga _1-z N Al _w Ga _1-w N/Al _z Ga _1-z N heterojunction is formed at , as shown in Figure 10;

The third step: Al _w Ga _1-w N/Al _z Ga _1-z N, Al _z Ga _1-z N/Al _y Ga _1-y N, Al _y Ga _{1 -y} /Al _x Ga _1-x N, Al _x Ga _1-x /GaN heterojunctions were ultrasonically cleaned, and after drying with nitrogen gas, the ohmic contact area was etched by ion etching. The etching gas was BCl ₃ , and then Use electron beam evaporation to grow ohmic contact electrodes (Ti/Al/Au) and rapidly anneal for about 30s in N2 atmosphere at 850°C, as shown in Figure 11;

Step 5: Evaporate and grow the metal electrode 102 in the groove with the electron beam, as shown in FIG. 12 .

Claims (10)

1. A high-voltage multi-heterojunction device with a normally-off channel, comprising a first semiconductor substrate layer (201), a second semiconductor buffer layer (202), and a third semiconductor layer (203) arranged in sequence from bottom to top , the fourth semiconductor layer (204) and the fifth semiconductor layer (205); the upper surfaces of both ends of the fourth semiconductor layer (204) are respectively provided with a first ohmic contact (101) and a second ohmic contact (103); The fifth semiconductor layer (205) has a metal electrode (102); the third semiconductor layer (203) and the fourth semiconductor layer (204) form a first heterojunction at the contact interface, and the fourth semiconductor layer The layer (204) and the fifth semiconductor layer (205) form a second heterojunction at the contact interface; it is characterized in that there is a non-planar heterojunction under the metal electrode (102) that interrupts the two-dimensional electron gas channel directly below it. texture. 2. A high-voltage multi-heterojunction device with a normally-off channel according to claim 1, wherein the non-planar heterojunction is recessed from the fifth semiconductor layer (205) through the fourth The semiconductor layer (204) is connected to the upper surface of the third semiconductor layer (203); a groove is formed between the fifth semiconductor layer (205) and the metal electrode (102), and the metal electrode (102) fills the groove In the groove; there is a sixth semiconductor layer (206) between the fifth semiconductor layer (205) and the metal electrode (102). 3. A high-voltage multi-heterojunction device with a normally-off channel according to claim 2, characterized in that, the two ends of the sixth semiconductor layer (206) are respectively connected to the first ohmic contact (101) and The second ohmic contact (103) is connected; there is also a seventh semiconductor layer (207) between the sixth semiconductor layer (206) and the metal electrode (102); the two ends of the seventh semiconductor layer (207) are respectively connected to The first ohmic contact (101) and the second ohmic contact (103) are connected. 4. A high-voltage multi-heterojunction device with a normally-off channel, comprising a first semiconductor substrate layer (201), a second semiconductor buffer layer (202), and a third semiconductor layer (203) arranged sequentially from bottom to top and a fourth semiconductor layer (204); the upper surfaces of both ends of the third semiconductor layer (203) are respectively provided with a first ohmic contact (101) and a second ohmic contact (103); the fourth semiconductor layer (204 ) are respectively connected to the first ohmic contact (101) and the second ohmic contact (103), the fourth semiconductor layer (204) has a metal electrode (102); the third semiconductor layer (203) is connected to The fourth semiconductor layer (204) forms a first heterojunction at the contact interface; it is characterized in that there is a non-planar heterojunction under the metal electrode (102) that interrupts the two-dimensional electron gas channel directly below it. 5. A kind of high-voltage multi-heterojunction device with a normally-off channel according to claim 4, characterized in that, the fourth type semiconductor layer (204) is composed of a bent surface and a horizontal plane; A non-planar heterojunction is formed at the bending surface of the semiconductor layer (204); the bending surface of the fourth semiconductor layer (204) is located directly under the metal electrode (102). 6. A high-voltage multi-heterojunction device with a normally-off channel according to claim 5, characterized in that, the bending surface of the fourth semiconductor layer (204) is bent upward, and the fourth The cross-sectional shape between the lower surface at the bending surface of the semiconductor layer (204) and the upper surface of the third semiconductor layer (203) is a trapezoid, the width of the lower base of the trapezoid is greater than the width of the upper base, and the third semiconductor layer The layer (203) is filled in the trapezoid and connected with the lower surface of the bending surface of the fourth semiconductor layer (204); there is also a fifth semiconductor layer ( 205), the fifth semiconductor layer (205) completely covers the upper surface of the fourth semiconductor layer (204); the metal electrode (102) covers the upper surface of the bending surface part of the fifth semiconductor layer (205) . 7. A high-voltage multi-heterojunction device with a normally-off channel according to claim 5, characterized in that, the bending surface of the fourth semiconductor layer (204) is bent upward, and the fourth The cross-sectional shape between the lower surface at the bending surface of the semiconductor layer (204) and the upper surface of the third semiconductor layer (203) is a trapezoid, and the width of the lower base of the trapezoid is greater than the width of the upper base; There is an eighth semiconductor layer (208), and a second heterojunction is formed at the junction of the eighth semiconductor layer (208) and the fourth semiconductor layer; the metal electrode (102) covers the fourth semiconductor layer (204) The top surface of the curved face. 8. A high-voltage multi-heterojunction device with a normally-off channel according to claim 5, characterized in that, the bending surface of the fourth semiconductor layer (204) is bent upwards, and the fourth The cross-sectional shape between the lower surface at the bending surface of the semiconductor layer (204) and the upper surface of the third semiconductor layer (203) is a trapezoid, and the width of the lower base of the trapezoid is greater than the width of the upper base; the third semiconductor The layer (203) is filled in a trapezoid; the metal electrode (102) is composed of a first vertical plane, a second vertical plane and a plane; the plane of the metal electrode (102) is mutually connected with the horizontal plane of the fourth semiconductor layer (204) Parallel; the plane of the metal electrode (102) is connected with the first vertical plane of the metal electrode (102) and the second vertical plane of the metal electrode (102) to form an inverted U-shaped structure; the plane of the metal electrode (102) is connected with the second vertical plane of the metal electrode (102); The first vertical plane of the metal electrode (102) and the second vertical plane of the metal electrode (102) are perpendicular to each other; the lower surface of the first vertical plane of the metal electrode (102) and the bending plane of the fourth semiconductor layer (204) The horizontal surface on one side is connected to the surface, and its upper surface is connected to the lower surface of one end of the plane of the metal electrode (102); the lower surface of the second vertical plane of the metal electrode (102) is connected to the bent surface of the fourth semiconductor layer (204) The upper surface of the horizontal plane on the other side is connected, and its upper surface is connected with the lower surface of the other end of the plane of the metal electrode (102); the plane of the metal electrode (102) is connected with the upper bottom surface of the bending surface of the fourth semiconductor layer (204) between the tenth semiconductor layer (210); the tenth semiconductor layer (210), the vertical surface of the metal electrode (102), the level of the metal electrode (102) and the bending surface of the fourth semiconductor layer (204) There is a ninth semiconductor layer (209) between them. 9. A high-voltage multi-heterojunction device with a normally-off channel according to claim 5, characterized in that, the bending surface of the fourth semiconductor layer (204) is under the fourth semiconductor layer (204). Concave formation, the cross-sectional shape between the upper surface of the fourth semiconductor layer (204) at the bend and the horizontal plane of the fourth semiconductor layer (204) is a trapezoid, the width of the lower base of the trapezoid is greater than the width of the upper base; The metal electrode (102) is composed of a plane and a vertical surface, the plane lower surface of the metal electrode (102) and the upper surface of the fourth semiconductor layer (204) are located on the same plane, and the vertical surface of the metal electrode (102) is arranged in a trapezoidal shape. In the bending surface; the plane of the metal electrode (102) is perpendicular to the vertical plane of the metal electrode (102) to form a T-shaped structure; the vertical plane of the metal electrode (102) and the upper surface of the fourth semiconductor layer (204) are There is a tenth semiconductor layer (210) between them, and a ninth semiconductor layer (209) between it and the sides of the trapezoidal bending surface. 10. A high-voltage heterojunction device with a normally-off channel according to any one of claims 4-9, characterized in that the first semiconductor substrate layer (201) is made of sapphire, silicon and silicon carbide a kind of; the second type of semiconductor (202) is a kind of SiC, AlN, GaN, AlGaN; the third semiconductor layer (203), the fourth semiconductor layer (204), the eighth semiconductor layer ( 208), the ninth semiconductor layer (209) and the tenth semiconductor layer (210) are III-V compounds; the electrode materials of the first ohmic contact (101) and the second ohmic contact (103) are gold and silver , aluminum, titanium, platinum and indium in one or more combinations; the material used in the metal electrode (102) is titanium, gold, nickel, platinum, nuclei, tungsten, silver, aluminum, titanium, molybdenum and indium one or more combinations of .