CN116978944A - High electron mobility transistor and preparation method thereof - Google Patents

Abstract

The invention provides a high electron mobility transistor and a preparation method. The high electron mobility transistor includes a composite insertion layer and a channel layer deposited on the composite insertion layer; the channel layer is an InGaN channel layer, The composite insertion layer includes an electron blocking layer, a transition layer and an improvement layer deposited in sequence. The electron blocking layer includes periodically alternately grown Ga ₂ O ₃ layers and nitrogen polarity AlGaN layers. The transition layer is gallium polarity. AlInGaN transition layer, the improvement layer is a nitrogen polarity InGaN improvement layer, the Al component of the gallium polarity AlInGaN transition layer gradually decreases along the growth direction of the gallium polarity AlInGaN transition layer, the gallium polarity AlInGaN transition layer Its In component gradually increases along the growth direction of the gallium polar AlInGaN transition layer, which can produce a higher concentration of two-dimensional electron gas concentration, and the deeper InGaN potential well of InGaN is also more conducive to limiting the generated two-dimensional electron gas. , and InGaN’s deeper InGaN potential well is also more conducive to confining the generated two-dimensional electron gas.

Description

A high electron mobility transistor and preparation method

Technical field

The invention belongs to the field of semiconductor technology, and specifically relates to a high electron mobility transistor and a preparation method.

Background technique

The epitaxial structure of a conventional AlGaN/GaN heterostructure high electron mobility transistor includes a substrate, a nucleation layer, a buffer layer, a GaN channel layer, an AlN insertion layer, an AlGaN barrier layer, and a GaN cap layer;

However, existing high electron mobility transistors have the following shortcomings:

1. In the AlGaN/GaN heterostructure, the GaN channel layer has limited ability to confine two-dimensional electrons due to its limited potential well depth. The two-dimensional electron gas concentration is relatively low, and the electron mobility capability is relatively weak. The device The short channel effect is obvious, which affects the operating frequency and output power of the device.

2. The GaN channel layer is affected by the compressive stress of the buffer layer, causing a built-in electric field in the channel layer from the barrier layer to the buffer layer. This built-in electric field will reduce the two-dimensional electron gas concentration of the channel layer.

3. GaN channel layer electrons are more likely to leak into the buffer layer, causing a current collapse effect, which also weakens the two-dimensional confinement characteristics of the GaN channel layer and reduces the two-dimensional electron gas concentration, which limits the output of high-frequency and high-power devices. , reduces the breakdown voltage of the device and affects the reliability of the device. Therefore, in order to improve the operating frequency, output power and reliability of the device, it is crucial to prepare devices with high two-dimensional electron gas concentration and low buffer layer leakage current.

Contents of the invention

In order to solve the above technical problems, the present invention provides a high electron mobility transistor and a preparation method to solve the technical problem of low concentration of two-dimensional electron gas in the channel layer.

On the one hand, the invention provides the following technical solution: a high electron mobility transistor, including a composite insertion layer and a channel layer deposited on the composite insertion layer;

The channel layer is an InGaN channel layer. The composite insertion layer includes an electron blocking layer, a transition layer and an improvement layer deposited in sequence. The electron blocking layer includes periodically alternately grown Ga ₂ O ₃ layers and nitrogen polarity layers. AlGaN layer, the transition layer is a gallium polarity AlInGaN transition layer, the improvement layer is a nitrogen polarity InGaN improvement layer, the Al component of the gallium polarity AlInGaN transition layer is along the growth direction of the gallium polarity AlInGaN transition layer Gradually decreases, and the In composition of the gallium polar AlInGaN transition layer gradually increases along the growth direction of the gallium polar AlInGaN transition layer.

Compared with the existing technology, the beneficial effects of the present invention are: first, the InGaN channel layer and the AlGaN barrier layer can produce a higher concentration of two-dimensional electron gas concentration due to their strong polarization, and InGaN has a deeper The InGaN potential well is also more conducive to confining the generated two-dimensional electron gas;

Second, the introduction of the nitrogen polarity InGaN improvement layer in the composite insertion layer can provide a good growth platform for the InGaN channel layer and improve the crystal quality of the InGaN channel layer. On the other hand, it also avoids the channel layer being directly affected by the buffer layer, The electron blocking layer and transition layer compressive stress in the composite insertion layer reduce the built-in electric field in the InGaN channel layer from the AlGaN barrier layer along the direction of the buffer layer, thereby improving the ability of the built-in electric field to reduce the two-dimensional electron gas concentration in the channel layer. problem, and the polarity reversal of the nitrogen polarity InGaN improvement layer, when the channel layer is subjected to compressive stress, the built-in electric field reversal further increases the two-dimensional electron gas concentration of the InGaN channel layer, improving The operating frequency and output power of the device are determined;

Third, along the growth direction of the epitaxial layer of the gallium polar AlInGaN transition layer in the composite insertion layer, the Al component gradually decreases and the In component gradually increases, which improves the layer lattice of the electron blocking layer and nitrogen polarity InGaN in the composite insertion layer. Better matching, improves the crystal quality of the nitrogen polarity InGaN improvement layer, and the built-in electric field generated by the gallium polarity AlInGaN transition layer when subjected to the compressive stress of the electron blocking layer in the composite insertion layer can cause the channel layer to migrate to the buffer layer The electrons reflow and reduce the leakage current of the buffer layer.

Fourth, the Ga ₂ O ₃ layer in the electron blocking layer in the composite insertion layer has a high band gap, which can effectively block the migration of electrons from the channel layer to the buffer layer. On the other hand, the nitrogen polar AlGaN layer is affected by Ga ₂ O ₃ The built-in electric field generated by the tensile stress of the layer is consistent with the built-in electric field of the gallium polar AlInGaN transition layer in the composite insertion layer, which strengthens the reflow ability of electrons migrating from the channel layer to the buffer layer, and periodically alternates the growth of Ga ₂ O ₃ layers And the nitrogen polarity AlGaN layer greatly reduces the leakage current of the buffer layer, improves the device's ability to withstand breakdown voltage, and improves reliability performance.

Further, the thickness range of the Ga ₂ O ₃ layer is 50 nm -200 nm, the thickness range of the nitrogen polar AlGaN layer is 100 nm -400 nm, and the thickness range of the gallium polar AlInGaN transition layer is 50 nm - 300nm, and the thickness of the nitrogen polarity InGaN improvement layer ranges from 100nm to 400nm.

Further, the Al component range of the gallium polar AlInGaN transition layer is 0-0.2, and the In component range of the gallium polar AlInGaN transition layer is 0.05-0.3.

Further, the high electron mobility transistor further includes a substrate, a buffer layer, an AlN insertion layer, a barrier layer and a cap layer. The buffer layer, the composite insertion layer, the channel layer, the AlN insertion layer layer, the barrier layer and the capping layer are sequentially deposited on the substrate.

Further, the thickness of the buffer layer ranges from 1.4 μm to 2.8 μm, the thickness of the channel layer ranges from 50 nm to 300 nm, the thickness of the barrier layer ranges from 10 nm to 45 nm, and the thickness of the cap layer The range is 10nm-50nm, the barrier layer is an AlGaN barrier layer, and the capping layer is a GaN capping layer.

Further, the alternate growth period of the Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer in the electron blocking layer ranges from 2 to 6.

On the other hand, the present invention also proposes a method for preparing a high electron mobility transistor, which method includes the following steps:

provide a substrate;

depositing a buffer layer on the substrate;

A composite insertion layer is deposited on the buffer layer, wherein the composite insertion layer includes an electron blocking layer, a transition layer and an improvement layer deposited in sequence, and the electron blocking layer includes periodically alternately grown Ga ₂ O ₃ layers and nitrogen. Polar AlGaN layer, the transition layer is a gallium polar AlInGaN transition layer, the improvement layer is a nitrogen polarity InGaN improvement layer, the Al component of the gallium polar AlInGaN transition layer is along the gallium polarity AlInGaN transition layer The growth direction gradually decreases, and the In component of the gallium polar AlInGaN transition layer gradually increases along the growth direction of the gallium polar AlInGaN transition layer;

Deposit a channel layer on the composite insertion layer, wherein the channel layer is an InGaN channel layer;

depositing an AlN insertion layer on the channel layer;

depositing a barrier layer on the AlN insertion layer;

A capping layer is deposited on the barrier layer.

Further, the molar flow ratio of the N source to the Ga source for growing the nitrogen polar AlGaN layer in the electron blocking layer is greater than or equal to 1,400.

Further, the molar flow ratio of the N source to the Ga source for growing the gallium polar AlInGaN transition layer is less than or equal to 300.

Further, the molar flow ratio of the N source to the Ga source for growing the nitrogen polarity InGaN improvement layer is greater than or equal to 1,400.

Description of the drawings

FIG. 1 is a schematic structural diagram of a high electron mobility transistor in the first embodiment of the present invention.

FIG. 2 is a flow chart of a method for manufacturing a high electron mobility transistor in the second embodiment of the present invention.

Description of main component symbols: 1. Substrate; 2. Buffer layer; 3. Composite insertion layer; 4. InGaN channel layer; 5. AlN insertion layer; 6. Barrier layer; 7. Capping layer; 31. Electronic blocking layer ; 32. Gallium polarity AlInGaN transition layer; 33. Nitrogen polarity InGaN improvement layer.

The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings.

Detailed ways

In order to facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Several embodiments of the invention are shown in the drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It should be noted that when an element is referred to as being "mounted" on another element, it can be directly on the other element or intervening elements may also be present. When an element is said to be "connected" to another element, it can be directly connected to the other element or there may also be intervening elements present. The terms "vertical," "horizontal," "left," "right" and similar expressions are used herein for illustrative purposes only.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which the invention belongs. The terminology used herein in the description of the invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Embodiment 1

Please refer to Figure 1, which shows a high electron mobility transistor in a first embodiment of the present invention, including a substrate 1 and a buffer layer 2, a composite insertion layer 3, a channel layer, and a buffer layer 2 deposited on the substrate 1 in sequence. AlN insertion layer 5, barrier layer 6 and capping layer 7.

Wherein, the channel layer is an InGaN channel layer 4, and the composite insertion layer 3 includes an electron blocking layer 31, a transition layer and an improvement layer deposited in sequence, and the electron blocking layer 31 includes periodically alternately grown Ga ₂ O ₃ layers and a nitrogen polarity AlGaN layer, the transition layer is a gallium polarity AlInGaN transition layer 32, the improvement layer is a nitrogen polarity InGaN improvement layer 33, the Al component of the gallium polarity AlInGaN transition layer is along the The growth direction of the gallium polar AlInGaN transition layer gradually decreases, and the In component of the gallium polar AlInGaN transition layer gradually increases along the growth direction of the gallium polar AlInGaN transition layer.

Specifically, the thickness of the Ga ₂ O ₃ layer ranges from 50 nm to 200 nm, the thickness of the nitrogen polar AlGaN layer ranges from 100 nm to 400 nm, and the thickness of the gallium polar AlInGaN transition layer 32 ranges from 50 nm. -300nm, and the thickness of the nitrogen polarity InGaN improvement layer 33 ranges from 100nm -400nm. Optionally, the thickness of the Ga ₂ O ₃ layer is 50 nm, 100 nm, or 200 nm, the thickness of the nitrogen polar AlGaN layer is 100 nm, 200 nm, 250 nm, 300 nm, or 400 nm, and the gallium electrode The thickness of the polar AlInGaN transition layer 32 is 50 nm, 100 nm, 175 nm, 200 nm or 300 nm, and the thickness of the nitrogen polar InGaN improvement layer 33 is in the range of 100 nm, 200 nm, 250 nm, 300 nm or 400 nm.

Specifically, the Al composition range of the gallium polar AlInGaN transition layer 32 is 0-0.2, and the In composition range of the gallium polar AlInGaN transition layer 32 is 0.05-0.3. Optionally, the Al composition of the gallium polar AlInGaN transition layer 32 decreases from 0.15 to 0 along the growth direction of the gallium polar AlInGaN transition layer 32, or the Al composition of the gallium polar AlInGaN transition layer 32 decreases along the growth direction of the gallium electrode. The growth direction of the gallium polar AlInGaN transition layer 32 decreases from 0.2 to 0, and the In component of the gallium polar AlInGaN transition layer 32 increases from 0.05 to 0.3 along the growth direction of the gallium polar AlInGaN transition layer 32, or the gallium polar AlInGaN transition layer The In composition of layer 32 increases from 0.1 to 0.25 along the growth direction of the gallium polar AlInGaN transition layer 32 .

Specifically, the thickness of the buffer layer 2 ranges from 1.4 μm to 2.8 μm, the thickness of the channel layer ranges from 50 nm to 300 nm, the thickness of the barrier layer 6 ranges from 10 nm to 45 nm, and the cap layer The thickness range of 7 is 10 nm-50 nm, the barrier layer 6 is an AlGaN barrier layer, and the cap layer 7 is a GaN cap layer. Optionally, the thickness of the buffer layer 2 is 1.4 μm, 2.1 μm or 2.8 μm, the thickness of the channel layer is 50 nm, 160nm or 300nm, and the thickness of the barrier layer 6 is 10 nm, 25 nm. Or 45nm, and the thickness of the capping layer 7 is 10nm, or 30nm, or 50nm.

The alternate growth period of the Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer in the electron blocking layer 31 is 2, 4 or 6.

In this embodiment, the value of the alternating growth cycle of the Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer in the middle layer of the electron blocking layer 31 is 4, where the single layer thickness of the Ga ₂ O ₃ layer is 100nm, the single layer thickness of nitrogen polar AlGaN layer growth is 250nm;

The transition layer is a gallium polar AlInGaN transition layer 32. The Al component of the gallium polar AlInGaN transition layer 32 decreases from 0.15 to 0 along the growth direction of the gallium polar AlInGaN transition layer 32. The gallium polar AlInGaN transition layer The 32In component increases from 0.1 to 0.25 along the growth direction of the gallium polar AlInGaN transition layer 32, where the thickness of the gallium polar AlInGaN transition layer 32 is 175 nm;

The improvement layer is a nitrogen polarity InGaN improvement layer 33, and its growth thickness is 250nm;

The channel layer is InGaN channel layer 4 .

In order to facilitate subsequent testing and understanding, experimental group one, experimental group two, experimental group three, experimental group four, experimental group five, experimental group six, experimental group seven, experimental group eight, experimental group nine and Control group one and control group two;

Among them, experimental group 1, experimental group 2, experimental group 3, experimental group 4, experimental group 5, experimental group 6, experimental group 7, experimental group 8, and experimental group 9 all adopt high electron mobility as described in Example 1. The transistors all include the composite insertion layer 3 and the InGaN channel layer 4 in Embodiment 1, while Control Groups 1 and 2 use transistors in the prior art. Their structures are the same as those in Embodiment 1, but the differences are as follows: In the control group 1, the prior art is used without the composite insertion layer 3. In the control group 2, the channel layer in the prior art is used as a GaN channel layer.

Specifically, the electron blocking layer 31 (the Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer) in the experimental group 1 has an alternate growth period value of 4, a Ga ₂ O ₃ layer thickness of 100 nm, and a nitrogen polar AlGaN layer thickness. 250 nm, the thickness of the gallium polar AlInGaN transition layer 32 is 175 nm, and the thickness of the nitrogen polarity InGaN improvement layer 33 is 250 nm;

The electron blocking layer 31 (the Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer) in the experimental group 2 has an alternate growth period value of 2, the thickness of the Ga ₂ O ₃ layer is 100 nm, and the thickness of the nitrogen polar AlGaN layer is 250 nm. The thickness of the gallium polar AlInGaN transition layer 32 is 175 nm, and the thickness of the nitrogen polarity InGaN improvement layer 33 is 250 nm;

The electron blocking layer 31 (the Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer) in experimental group three has an alternate growth period value of 6, a Ga ₂ O ₃ layer thickness of 100 nm, and a nitrogen polar AlGaN layer thickness of 250 nm. The thickness of the gallium polar AlInGaN transition layer 32 is 175 nm, and the thickness of the nitrogen polarity InGaN improvement layer 33 is 250 nm;

The electron blocking layer 31 (the Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer) in experimental group 4 has an alternate growth period value of 4, a Ga ₂ O ₃ layer thickness of 50 nm, a nitrogen polar AlGaN layer thickness of 100 nm, and gallium The thickness of the polar AlInGaN transition layer 32 is 175 nm, and the thickness of the nitrogen polar InGaN improvement layer 33 is 250 nm;

The electron blocking layer 31 in experimental group five (the Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer) has an alternate growth period value of 4, a Ga ₂ O ₃ layer thickness of 200 nm, a nitrogen polar AlGaN layer thickness of 400 nm, and a gallium electrode. The thickness of the polar AlInGaN transition layer 32 is 175 nm, and the thickness of the nitrogen polar InGaN improvement layer 33 is 250 nm;

The electron blocking layer 31 (the Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer) in experimental group six has an alternate growth period value of 4, the thickness of the Ga ₂ O ₃ layer is 100 nm, and the thickness of the nitrogen polar AlGaN layer is 250 nm. The thickness of the gallium polar AlInGaN transition layer 32 is 50 nm, and the thickness of the nitrogen polar InGaN improvement layer 33 is 250 nm;

The electron blocking layer 31 (the Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer) in experimental group seven has an alternate growth period value of 4, the thickness of the Ga ₂ O ₃ layer is 100 nm, and the thickness of the nitrogen polar AlGaN layer is 250 nm. The thickness of the gallium polar AlInGaN transition layer 32 is 300 nm, and the thickness of the nitrogen polarity InGaN improvement layer 33 is 250 nm;

The electron blocking layer 31 (the Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer) in experimental group eight has an alternate growth period value of 4, the thickness of the Ga ₂ O ₃ layer is 100 nm, and the thickness of the nitrogen polar AlGaN layer is 250 nm. The thickness of the gallium polar AlInGaN transition layer 32 is 175 nm, and the thickness of the nitrogen polarity InGaN improvement layer 33 is 100 nm;

The electron blocking layer 31 (the Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer) in experimental group nine has an alternate growth period value of 4, the thickness of the Ga ₂ O ₃ layer is 100 nm, and the thickness of the nitrogen polar AlGaN layer is 250 nm. The thickness of the gallium polar AlInGaN transition layer 32 is 175 nm, and the thickness of the nitrogen polarity InGaN improvement layer 33 is 400 nm.

The two-dimensional electrons in the above experimental groups one, two, three, four, five, six, seven, eight, nine and the control groups one and two are Gas concentration and buffer layer 2 leakage current were tested. The test results are shown in the following table:

It can be seen from the above table that the first and two-dimensional electron gas concentrations of the experimental group are 3.4×10 ¹³ cm ^-2 and the leakage current of buffer layer 2 is 8.7×10 ^-4 A/mm;

Experimental group 2, the two-dimensional electron gas concentration is 3.2×10 ¹³ cm ^-2 , and the leakage current of buffer layer 2 is 4.15×10 ^-3 A/mm;

Experimental group three, the two-dimensional electron gas concentration is 2.9×10 ¹³ cm ^-2 and the leakage current of buffer layer 2 is 9.3×10 ^-4 A/mm;

Experimental group 4. The two-dimensional electron gas concentration is 3.0×10 ¹³ cm ^-2 and the leakage current of buffer layer 2 is 3.2×10 ^-3 A/mm;

Experimental group 5. The two-dimensional electron gas concentration is 2.7×10 ¹³ cm ^-2 and the leakage current of buffer layer 2 is 1.08×10 ^-3 A/mm;

Experimental group 6. The two-dimensional electron gas concentration is 2.3×10 ¹³ cm ^-2 and the leakage current of buffer layer 2 is 9.96×10 ^-4 A/mm;

Experimental group 7. The two-dimensional electron gas concentration is 3.0×10 ¹³ cm ^-2 and the leakage current of buffer layer 2 is 8.5×10 ^-4 A/mm;

Experimental group 8. The two-dimensional electron gas concentration is 8.7×10 ¹² cm ^-2 and the leakage current of buffer layer 2 is 8.1×10 ^-4 A/mm;

Experimental group 9. The two-dimensional electron gas concentration is 3.3×10 ¹³ cm ^-2 and the leakage current of buffer layer 2 is 1.2×10 ^-4 A/mm;

In control group 1, the two-dimensional electron gas concentration is 1.1×10 ¹³ cm ^-2 and the leakage current of buffer layer 2 is 7.4×10 ^-2 A/mm;

In control group 2, the two-dimensional electron gas concentration is 2.8×10 ¹² cm ^-2 and the leakage current of buffer layer 2 is 6.7×10 ^-4 A/mm.

As can be seen from the above table, according to the experimental data of the above-mentioned experimental examples and comparative examples of the present invention, compared with the traditional preparation method, the transistor prepared using the preparation method disclosed in the present invention has an increased two-dimensional electron gas concentration and a reduced buffer. Layer 2 leakage current, thereby improving device reliability. It improves the problem that the two-dimensional electron gas concentration in the channel layer is low and the output of high-frequency and high-power devices is limited. The problem of large leakage current and low breakdown voltage capability of the buffer layer 2 is reduced, and the reliability of the device is improved.

Embodiment 2

Please refer to Figure 2, which shows a method for preparing a high electron mobility transistor in a second embodiment of the present invention. The method includes the following steps: steps S01~S07;

S01: Provide a substrate 1;

The substrate 1 includes but is not limited to a silicon substrate, a sapphire substrate, a silicon carbide substrate, and a GaN substrate; as an example of the present invention, a silicon substrate is used as the epitaxial layer growth substrate in this example.

S02: Deposit buffer layer 2 on the substrate 1;

The buffer layer 2 includes but is not limited to any one of AlN, AlGaN, GaN or a combination thereof. As an example of the present invention, the nucleation layer is an AlGaN buffer layer, and the N (nitrogen) source can be NH ₃ , Ga (gallium) ) source can be TMGa, Al (aluminum) source can be TMAl, the specific deposition process is, the reaction chamber temperature can be 750℃-1050℃, the chamber pressure can be 100 torr -200torr, and the growth thickness can be 1.4 μm -2.8μm , specifically, the thickness of the AlGaN buffer layer may be 2.1 μm.

S03: Deposit composite insertion layer 3 on the buffer;

The composite insertion layer 3 includes an electron blocking layer 31, a transition layer, and an improvement layer deposited in sequence;

The electron blocking layer 31 is a periodically alternately grown Ga ₂ O ₃ layer and a nitrogen polar AlGaN layer; the transition layer is a gallium polar AlInGaN transition layer 32; the Al component of the gallium polar AlInGaN transition layer is along The growth direction of the epitaxial layer gradually decreases, and its In composition gradually increases along the growth direction of the epitaxial layer; the improvement layer is the nitrogen polarity InGaN improvement layer 33;

The specific process of depositing the electron blocking layer 31 is to introduce the O (oxygen) source and Ga (gallium) source required for growth into the reaction chamber, maintain the reaction chamber temperature at 800°C-1200°C, and the reaction chamber pressure at 150 torr-200torr. Grow a Ga ₂ O ₃ layer with a single layer thickness of 200nm-500nm, then stop feeding the O (oxygen) source, and feed the N (nitrogen) source, Al (aluminum) source, and Ga (gallium) source into the reaction chamber, where The ratio of the molar flow rate of the N (nitrogen) source to the molar flow rate of the Ga (gallium) source entering the reaction chamber is ≥1400. The reaction chamber pressure can be 50 torr -200torr, and a nitrogen polar AlGaN layer with a single layer thickness of 100nm-400nm is grown. The grown electron blocking layer 31 is composed of 2-6 periodically alternately grown Ga ₂ O ₃ layers and nitrogen polar AlGaN layers.

The specific process of depositing the transition layer is to introduce the N (nitrogen) source, Al (aluminum) source, Ga (gallium) source, and In (indium) source required for growth into the reaction chamber. ) source to the molar flow rate of the Ga (gallium) source ≤ 300, the reaction chamber temperature is 800℃-1050℃, the reaction chamber pressure can be 150 torr -250torr, the growth Al component is 0-0.15, and the In component A gallium polar AlInGaN transition layer 32 with a thickness of 50 nm to 300 nm is 0.15-0.25, in which the Al component gradually decreases along the growth direction, and the In component gradually increases along the growth direction.

The specific process for depositing the improvement layer is to introduce the N (nitrogen) source, Ga (gallium) source, and In (indium) source required for growth into the reaction chamber. The molar flow rate of the N (nitrogen) source into the reaction chamber is equal to The molar flow ratio of the Ga (gallium) source is ≥1400, the reaction chamber temperature is 800°C-1000°C, the reaction chamber pressure can be 150 torr-300torr, and a nitrogen polarity InGaN improvement layer 33 with a single layer thickness of 100nm-400nm is grown.

S04: Deposit a channel layer on the composite insertion layer 3 .

As an example of the present invention, the channel layer is an InGaN channel layer. The specific deposition process of the InGaN channel layer is: the reaction chamber temperature can be 650°C-950°C, and the reaction chamber pressure can be 50 torr-200torr, N The (nitrogen) source can be NH ₃ , the Ga (gallium) source can be TEGa, the In (indium) source can be TMIn, and the growth thickness can be 50 nm-300nm. Specifically, as an example of the present invention, the InGaN channel layer 4 The thickness can be 160nm.

S05: Deposit an AlN insertion layer 5 on the channel layer;

As an example of the present invention, the N (nitrogen) source can be NH ₃ and the Al (aluminum) source can be TMGa. The specific deposition process of the AlN insertion layer 5 is: the reaction chamber temperature can be 750°C-1050°C, and the reaction chamber pressure It can be 100 torr -150torr, the growth thickness can be 1 nm -6nm, and the specific thickness of the AlN insertion layer 5 can be 4nm.

S06: Deposit barrier layer 6 on the AlN insertion layer 5;

As an example of the present invention, the barrier layer 6 is an AlGaN barrier layer, the N (nitrogen) source can be NH3, the Al (aluminum) source can be TMAl, the Ga (gallium) source can be TEGa, and the reaction chamber temperature can be The temperature is 850℃-1150℃, the reaction chamber pressure can be 100 torr-200torr, the AlGaN barrier layer growth thickness can be 10 nm-45nm, and the specific AlGaN barrier layer thickness can be 25nm.

S07: Deposit the capping layer 7 on the barrier layer 6;

The cap layer 7 is a GaN cap layer, the N (nitrogen) source can be NH3, the Ga (gallium) source can be TEGa, the reaction chamber temperature can be 750°C-1100°C, and the reaction chamber pressure can be 150 torr-250torr. The thickness can be 10 nm-50nm. Specifically, the thickness of the GaN cap layer can be 30nm.

To sum up, in the high electron mobility transistor and the preparation method in the above embodiments of the present invention, first, the InGaN channel layer 4 and the AlGaN barrier layer can generate a higher concentration of two-dimensional electron gas concentration due to their strong polarization. , and the deeper InGaN potential well of InGaN is also more conducive to confining the generated two-dimensional electron gas;

Second, the introduction of the nitrogen polarity InGaN improvement layer 33 in the composite insertion layer 3 can provide a good growth platform for the InGaN channel layer 4 and improve the crystal quality of the InGaN channel layer 4. On the other hand, it also avoids direct contact between the channel layer and the InGaN channel layer 4. Due to the compressive stress of the electron blocking layer 31 in the buffer layer 2, the composite insertion layer 3 and the transition layer, the built-in electric field from the AlGaN barrier layer in the InGaN channel layer 4 along the direction of the buffer layer 2 is reduced, thereby improving the built-in electric field reduction The problem of two-dimensional electron gas concentration in the channel layer, and the polarity reversal of the nitrogen polarity InGaN improvement layer 33, which generates a built-in electric field reversal when the channel layer is subjected to compressive stress, further improves the performance of the InGaN channel. The two-dimensional electron gas concentration in channel layer 4 increases the operating frequency and output power of the device;

Third, along the growth direction of the epitaxial layer, the Al component of the gallium polar AlInGaN transition layer 32 in the composite insertion layer 3 gradually decreases, and the In component gradually increases, which improves the relationship between the electron blocking layer 31 in the composite insertion layer 3 and the nitrogen polarity InGaN. The lattice of the improvement layer 33 is more matched, improving the crystal quality of the nitrogen polarity InGaN improvement layer 33, and the built-in electric field generated by the gallium polarity AlInGaN transition layer when subjected to the compressive stress of the electron blocking layer 31 in the composite insertion layer 3 can The electrons migrating from the channel layer to the buffer layer 2 are reflowed, thereby reducing the leakage current of the buffer layer 2 .

Fourth, the Ga ₂ O ₃ layer in the electron blocking layer 31 in the composite insertion layer 3 has a high bandgap, which can effectively block the migration of electrons from the channel layer to the buffer layer 2. On the other hand, the nitrogen polar AlGaN layer is affected by Ga The built-in electric field generated by the tensile stress of _{the 2} O ₃ layer is consistent with the built-in electric field of the gallium polar AlInGaN transition layer 32 in the composite insertion layer 3, which strengthens the reflow ability of electrons migrating from the channel layer to the buffer layer 2, and periodically grows alternately. The Ga ₂ O ₃ layer and the nitrogen polar AlGaN layer greatly reduce the leakage current of the buffer layer 2, improve the device's ability to withstand breakdown voltage, and improve the reliability performance.

In the description of this specification, reference to the terms "one embodiment," "some embodiments," "an example," "specific examples," or "some examples" or the like means that specific features are described in connection with the embodiment or example. , structures, materials or features are included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The above-described embodiments only express several implementation modes of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the patent scope of the present invention. It should be noted that for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the scope of protection of the patent of the present invention shall be determined by the appended claims.

Claims (10)

1. A high electron mobility transistor, characterized in that it includes a composite insertion layer and a channel layer deposited on the composite insertion layer; The channel layer is an InGaN channel layer. The composite insertion layer includes an electron blocking layer, a transition layer and an improvement layer deposited in sequence. The electron blocking layer includes periodically alternately grown Ga ₂ O ₃ layers and nitrogen polarity layers. AlGaN layer, the transition layer is a gallium polar AlInGaN transition layer, the improvement layer is a nitrogen polarity InGaN improvement layer, the Al component of the gallium polar AlInGaN transition layer is along the growth direction of the gallium polar AlInGaN transition layer Gradually decreases, and the In composition of the gallium polar AlInGaN transition layer gradually increases along the growth direction of the gallium polar AlInGaN transition layer. 2. The high electron mobility transistor according to claim 1, characterized in that the thickness of the Ga ₂ O ₃ layer ranges from 50 nm to 200 nm, and the thickness of the nitrogen polar AlGaN layer ranges from 100 nm to 400 nm. , the thickness of the gallium polar AlInGaN transition layer ranges from 50 nm to 300 nm, and the thickness of the nitrogen polar InGaN improvement layer ranges from 100 nm to 400 nm. 3. The high electron mobility transistor according to claim 1, wherein the Al component range of the gallium polar AlInGaN transition layer is 0-0.2, and the In component range of the gallium polar AlInGaN transition layer is 0.05-0.3. 4. The high electron mobility transistor according to any one of claims 1 to 3, characterized in that the high electron mobility transistor further includes a substrate, a buffer layer, an AlN insertion layer, a barrier layer and a cap layer, The buffer layer, the composite insertion layer, the channel layer, the AlN insertion layer, the barrier layer and the capping layer are sequentially deposited on the substrate. 5. The high electron mobility transistor according to claim 4, wherein the thickness of the buffer layer ranges from 1.4 μm to 2.8 μm, the thickness of the channel layer ranges from 50 nm to 300 nm, and the potential The thickness of the barrier layer ranges from 10 nm to 45 nm, the thickness of the cap layer ranges from 10 nm to 50 nm, the barrier layer is an AlGaN barrier layer, and the cap layer is a GaN cap layer. 6. The high electron mobility transistor according to claim 1, wherein the alternating growth period of the Ga ₂ O ₃ layer and the nitrogen polarity AlGaN layer in the electron blocking layer ranges from 2 to 6 . 7. A method for preparing a high electron mobility transistor according to any one of claims 1 to 6, characterized in that it includes the following steps: provide a substrate; depositing a buffer layer on the substrate; A composite insertion layer is deposited on the buffer layer, wherein the composite insertion layer includes an electron blocking layer, a transition layer and an improvement layer deposited in sequence, and the electron blocking layer includes periodically alternately grown Ga ₂ O ₃ layers and nitrogen. Polar AlGaN layer, the transition layer is a gallium polar AlInGaN transition layer, the improvement layer is a nitrogen polarity InGaN improvement layer, the Al component of the gallium polar AlInGaN transition layer is along the gallium polarity AlInGaN transition layer The growth direction gradually decreases, and the In component of the gallium polar AlInGaN transition layer gradually increases along the growth direction of the gallium polar AlInGaN transition layer; Deposit a channel layer on the composite insertion layer, wherein the channel layer is an InGaN channel layer; depositing an AlN insertion layer on the channel layer; depositing a barrier layer on the AlN insertion layer; A capping layer is deposited on the barrier layer. 8. The method for preparing a high electron mobility transistor according to claim 7, wherein the molar flow ratio of the N source to the Ga source for growing the nitrogen polar AlGaN layer in the electron blocking layer is greater than or equal to 1400 . 9. The method for preparing a high electron mobility transistor according to claim 7, wherein the molar flow ratio of the N source to the Ga source for growing the gallium polar AlInGaN transition layer is less than or equal to 300. 10. The method for preparing a high electron mobility transistor according to claim 7, wherein the molar flow ratio of the N source to the Ga source for growing the nitrogen polarity InGaN improvement layer is greater than or equal to 1400.