TW202501839A - Semiconductor device - Google Patents

Abstract

A semiconductor device includes a first semiconductor structure having a first conductive type and a first dopant, a second dopant, and a third dopant; a second semiconductor structure having a second conductive type different from the first conductive type; and an active structure between the first semiconductor structure and the second semiconductor structure. The doping concentration of the first dopant is less than 3.5×10 ¹⁷atoms/cm ³.The ratio of the doping concentration of the third dopant and the doping concentration of the second dopant is larger than 5. The first semiconductor structure includes Aluminum.

Description

Semiconductor components

The present invention relates to a semiconductor device, and in particular to a photovoltaic semiconductor device.

Semiconductor components have a wide range of uses, and the development and research of related materials are also ongoing. For example, III-V semiconductor materials containing group III and group V elements can be applied to various optoelectronic semiconductor components such as light-emitting chips (e.g., light-emitting diodes or laser diodes), light-absorbing chips (photodetectors or solar cells) or non-light-emitting chips (e.g., power components of switches or rectifiers), which can be used in lighting, medical, display, communication, sensing, power supply systems and other fields. With the development of technology, there are still many technical research and development needs for semiconductor components. Although existing semiconductor components generally meet various needs, they are not satisfactory in all aspects and still need further improvement.

A semiconductor device comprises a first semiconductor structure having a first conductivity type and including a first doping, a second doping and a third doping; a second semiconductor structure having a second conductivity type different from the first conductivity type; and an active structure located between the first semiconductor structure and the second semiconductor structure; wherein the doping concentration of the first doping is less than 3.5×10 ¹⁷ atoms/cm ³ , the ratio of the doping concentration of the third doping to the doping concentration of the second doping is greater than 5, and the first semiconductor structure contains aluminum.

In order to better understand the above and other aspects of the present disclosure, embodiments are specifically described below with reference to the accompanying drawings.

The following disclosure provides a number of embodiments or examples for implementing different elements of the subject matter provided. Specific examples of each element and its configuration are described below to simplify the description of the disclosed embodiments. Of course, these are merely examples and are not intended to limit the disclosed embodiments. For example, if the description refers to a first element formed on a second element, it may include an embodiment in which the first and second elements are directly in contact, and it may also include an embodiment in which an additional element is formed between the first and second elements so that they are not in direct contact.

Furthermore, spatially relative terms such as "under", "below", "lower", "above", "higher" and the like may be used to facilitate describing the relationship between one component or feature and another component or feature in the drawings. Spatially relative terms are used to include different orientations of the device in use or operation, as well as the orientations described in the drawings. When the device is rotated 90 degrees or in other orientations, the spatially relative adjectives used will also be interpreted based on the rotated orientation.

Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure belongs. It should be understood that these terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the background or context of the relevant technology and the present disclosure, and should not be interpreted in an idealized or overly formal manner unless specifically defined in the present disclosure embodiments.

The composition, dopant and defects of each layer included in the semiconductor device disclosed herein can be analyzed by any suitable method, such as secondary ion mass spectrometer (SIMS), transmission electron microscopy (TEM) or scanning electron microscope (SEM); the thickness of each layer can also be analyzed by any suitable method, such as transmission electron microscope or scanning electron microscope.

The semiconductor device disclosed herein may include a light-emitting chip (e.g., a light-emitting diode or a laser diode), a light-absorbing chip (e.g., a photodetector or a solar cell), or a non-light-emitting chip (e.g., a power element of a switch or a rectifier). The laser diode may be an edge emitting laser diode (EEL). In the various schematic diagrams and exemplary embodiments described below, similar element symbols are used to represent similar elements.

FIG. 1 is a cross-sectional schematic diagram of a semiconductor device 10 according to an embodiment of the present disclosure. The semiconductor device 10 comprises a substrate 100, a semiconductor stack 110 located on the substrate 100, an upper electrode 102 and a lower electrode 104, wherein the upper electrode 102 is located on the semiconductor stack 110 and the lower electrode 104 is located below the substrate 100. The substrate 100 has a first surface 100a and a second surface 100b opposite to the first surface 100a. The semiconductor stack 110 comprises a second semiconductor structure 112, an active structure 113 and a first semiconductor structure 111 stacked in sequence on the first surface 100a along the direction of the Z axis. The semiconductor device 10 may alternatively include a first protection layer 106 covering the semiconductor stack 110 and located below the upper electrode 102 , and a second protection layer 108 located between the first protection layer 106 and the upper electrode 102 .

FIG. 2 is a schematic cross-sectional view of a semiconductor stack 110 of a semiconductor device 10 according to an embodiment of the present disclosure. The semiconductor stack 110 includes a first semiconductor structure 111, a second semiconductor structure 112, and an active structure 113 located between the first semiconductor structure 111 and the second semiconductor structure 112. The first semiconductor structure 111 has a first conductivity type, and the second semiconductor structure 112 has a second conductivity type different from the first conductivity type. For example, the first semiconductor structure 111 is a p-type and the second semiconductor structure 112 is an n-type, or the first semiconductor structure 111 is an n-type and the second semiconductor structure 112 is a p-type. In this way, the first semiconductor structure 111 and the second semiconductor structure 112 can respectively provide holes and electrons or electrons and holes to combine in the active structure 113 and emit light.

The first semiconductor structure 111 contains aluminum (Al) and includes a first dopant, a second dopant, and a third dopant. The atomic weight of the second dopant is less than the atomic weight of the first dopant and the atomic weight of the third dopant, and the atomic weight of the third dopant is greater than the atomic weight of the first dopant. In this embodiment, the first dopant and the third dopant can make the same semiconductor material have different conductivity types. For example, the dopant concentration is 1 The first doping concentration is 10 ¹⁸ atoms/cm ³ or more. The third doping with a concentration of 10 ¹⁸ atoms/cm ³ or more can make the semiconductor material form n-type and p-type, or p-type and n-type. In this embodiment, the concentration of the third doping is greater than the concentration of the second doping, and the concentration of the second doping is greater than the concentration of the first doping; because the doping concentration of the third doping in the first semiconductor structure 111 is greater than the doping concentration of the first doping, the conductivity type of the first semiconductor structure 111 is determined by the third doping. In other words, the third doping makes the first semiconductor structure 111 have the first conductivity type. The third doping is intentional doping when growing the first semiconductor structure 111, while the first doping and the second doping are unintentional doping when growing the first semiconductor structure 111. Rather, they are inevitable doping caused by the deposition of specific elements on the epitaxial wafer during the crystal growth process. The third doping may be, for example, an element such as magnesium (Mg) or zinc (Zn). In this embodiment, the first doping is carbon (C), the second doping is hydrogen (H), and the third doping is magnesium (Mg). The material of the first semiconductor structure 111 in this embodiment is a compound containing nitrogen and aluminum, such as aluminum gallium nitride (AlGaN).

In one embodiment, the doping concentration of the first dopant in the first semiconductor structure 111 can be less than 3.5 by adjusting the process parameters such as the crystal growth temperature, the type of gas required for epitaxial growth, and the introduction time of the aforementioned gas. 10 ¹⁷ atoms/cm ³ , and the ratio of the doping concentration of the third doping to the doping concentration of the second doping is greater than 5, for example, 5 to 10, so that the semiconductor device 10 has a higher output power. In this embodiment, the ratio of the doping concentration of the third doping to the doping concentration of the first doping in the first semiconductor structure 111 is 25 to 100.

As shown in FIGS. 1 and 2, in this embodiment, the first semiconductor structure 111 includes a first sublayer 111a and a second sublayer 111b, and the first sublayer 111a is closer to the active structure 113 than the second sublayer 111b. FIG. 3 is a secondary ion mass spectrum (SIMS) diagram of the semiconductor device 10 of an embodiment of the present disclosure. The first doping is carbon (C), the second doping is hydrogen (H), and the third doping is magnesium (Mg). As shown in FIG. 3, the ratio of the doping concentration of the third doping to the doping concentration of the second doping of the first semiconductor structure 111 is about 5.6, and the doping concentration of the first doping is about 2.8. 10 ¹⁷ atoms/cm ^{3 .} The ratio of the doping concentration of the third doping to the doping concentration of the first doping in the first semiconductor structure 111 is approximately 62.5.

It can be observed from the SIMS image that the doping concentration of the third doping in the first sublayer 111a is less than the doping concentration of the third doping in the second sublayer 111b, thereby reducing the degree of absorption of light emitted by the active structure 113 by the first semiconductor structure 111, thereby obtaining a semiconductor device 10 with high output efficiency. In this embodiment, the doping concentration of the second doping in the first sublayer 111a is also less than the doping concentration of the second doping in the second sublayer 111b; the doping concentration of the first doping in the first sublayer 111a is substantially the same as the doping concentration of the first doping in the second sublayer 111b.

The second semiconductor structure 112 includes a first dopant, a second dopant, and a fourth dopant. The fourth dopant enables the second semiconductor structure 112 to have a second conductivity type. The fourth dopant and the first dopant with sufficient dopant concentration can enable the same semiconductor material to have the same conductivity type. For example, when the dopant concentration is 1 The first doping concentration is 10 ¹⁸ atoms/cm ³ or more. The fourth doping agent having an amount of 10 ¹⁸ atoms/cm ³ or more can make the semiconductor material form an n-type or p-type. In this embodiment, the doping concentration of the fourth doping agent in the second semiconductor structure 112 is greater than the doping concentration of the second doping agent, and the doping concentration of the fourth doping agent is greater than the doping concentration of the first doping agent, and the doping concentration of the first doping agent can be greater than or equal to the doping concentration of the second doping agent. The fourth doping is intentional doping when growing the second semiconductor structure 112, while the first doping and the second doping are unintentional doping when growing the second semiconductor structure 112. Rather, they are inevitable doping caused by the deposition of specific elements on the epitaxial wafer during the crystal growth process. The fourth doping may be, for example, an element such as silicon (Si) or carbon (C). In this embodiment, the first doping is carbon (C), the second doping is hydrogen (H), the third doping is magnesium (Mg), and the fourth doping is silicon (Si). The material of the second semiconductor structure 112 is a compound containing nitrogen and aluminum, such as aluminum gallium nitride (AlGaN).

As shown in FIG. 2 , in this embodiment, the semiconductor stack 110 further selectively includes a blocking layer 114 located between the first semiconductor structure 111 and the active structure 113, and a contact layer 115 located on the second sublayer 111b of the first semiconductor structure 111. The blocking layer 114 has a band gap greater than the band gap of the first semiconductor structure 111, and thus can be used to suppress overflow of carriers (e.g., electrons, holes). In this embodiment, the blocking layer 114 contains aluminum. The aluminum of the first semiconductor structure 111 has a first atomic percentage, and the aluminum of the blocking layer 114 has a second atomic percentage greater than the first atomic percentage, so that the blocking layer 114 has a higher energy gap. The first atomic percentage is, for example, 3% to 8%, and the second atomic percentage is, for example, 10% to 25%. The above atomic percentage refers to the proportion of the number of atoms of a certain element in the same group of elements in a compound. For example, the chemical formula of aluminum gallium nitride can be expressed as Al _X Ga _Y N. Al and Ga are elements of the same group, so X+Y=1, where, In this embodiment, the barrier layer 114 is located between the first sublayer 111a and the active structure 113, and the barrier layer 114 includes a third dopant, and the doping concentration of the third dopant in the barrier layer 114 is greater than the doping concentration of the third dopant in the first sublayer 111a. The doping concentration of the third dopant in the barrier layer 114 is less than the doping concentration of the third dopant in the second sublayer 111b, as shown in FIG. 3 . In detail, in the process design, when the doping concentration of the third doping in the blocking layer 114 is greater than the doping concentration of the third doping in the first sub-layer 111a, it can be ensured that there is enough third doping in the first sub-layer 111a, so that the first sub-layer 111a can provide an appropriate amount of carriers (such as electrons or holes) to improve the performance of the semiconductor device 10. The material of the blocking layer 114 in this embodiment is a compound containing nitrogen and aluminum, and the blocking layer 114 and the first semiconductor structure 111 are compounds with the same elements, such as aluminum gallium nitride (AlGaN).

In this embodiment, the contact layer 115 also has a third doping agent, and the doping concentration of the third doping agent in the contact layer 115 is greater than the doping concentration of the third doping agent in the first semiconductor structure 111, thereby providing a lower contact resistance between the semiconductor stack 110 and the upper electrode 102. In one embodiment, the third doping concentration of the contact layer 115 is greater than 1×10 ²⁰ atoms/cm ³ , and the third doping concentration of the first semiconductor structure 111 is between 5×10 ¹⁷ atoms/cm ³ and 5×10 ¹⁹ atoms/cm ³ , but the embodiments disclosed herein are not limited thereto.

In the present disclosure, the doping concentration is the average doping concentration in the thickness direction (such as the Z direction in FIG. 1). Since the above-mentioned layers (e.g., the first semiconductor structure 111, the first sublayer 111a, the second sublayer 111b, the barrier layer 114, the contact layer 115, the second semiconductor structure 112, etc.) are layer structures with a certain thickness, different doping concentrations may be present at different thickness positions of the same layer. The variation of the doping concentration may be caused intentionally (e.g., by introducing different flow rates of epitaxial gas sources during the epitaxial process) or unintentionally (e.g., by unavoidable factors during the epitaxial process).

As shown in FIG. 2 , the semiconductor stack 110 may further selectively include a first light-conducting layer 116 between the first semiconductor structure 111 and the active structure 113, and/or a second light-conducting layer 117 between the second semiconductor structure 112 and the active structure 113. In this embodiment, the first light-conducting layer 116 is located between the blocking layer 114 and the active structure 113. The refractive index of the first light-conducting layer 116 and the second light-conducting layer 117 is smaller than the refractive index of the active structure 113, and thus can be used to confine the light generated from the active structure 113.

The first semiconductor structure 111, the second semiconductor structure 112, the blocking layer 114, the contact layer 115, the first optical conductive layer 116 and the second optical conductive layer 117 are nitrogen-based semiconductors, as shown in the general formula _{InxAlyGa1 -xyN (} 0≦x, 0≦y, 0≦x+y≦1). The active structure 113 can be a group III-V binary compound semiconductor (for example, gallium arsenide (GaAs), indium phosphide (InP), gallium phosphide (GaP), gallium nitride (GaN)), a group III-V multi-element compound semiconductor (for example, aluminum gallium arsenide (AlGaAs), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), aluminum indium gallium nitride (AlInGaN), gallium arsenide phosphide (GaAsP), aluminum gallium indium phosphide (AlGaInP), aluminum indium gallium arsenide (AlInGaAs)) or a group II-VI binary compound semiconductor (for example, cadmium selenide (CdSe), cadmium sulfide (CdS), zinc selenide (ZnSe)).

Referring to FIGS. 1 and 2 , in order to increase the ratio of the fundamental mode to the lateral mode of light emission, the first semiconductor structure 111 further includes a base 1111 and a ridge 1112 protruding from the base 1111. In one embodiment, the ridge 1112 is formed by removing a portion of the second sublayer 111b and a portion of the first sublayer 111a by yellow light development and etching after forming the first semiconductor structure 111, and the portion of the second sublayer 111b and the portion of the first sublayer 111a that are not removed constitute the ridge 1112. The semiconductor device 10 of this embodiment is a laser device. The active structure 113 has two corresponding end faces (not shown). The two end faces form a resonant cavity. The light emitted from the active structure 113 resonates back and forth between the two end faces and generates laser light. The laser light can be visible light or non-visible light, for example: blue light with a wavelength of 400 nm to 500 nm.

The contact layer 115 is disposed on the ridge 1111 of the first semiconductor structure 111, and the upper electrode 102 covers the ridge 1111 and is electrically connected to the first semiconductor structure 111. The first protective layer 106 is used to protect the sidewalls of the semiconductor stack 110, and the first protective layer 106 extends to cover the upper surface of the base 1111, two opposite sides of the ridge 1112, a portion of the upper surface of the contact layer 115, and a portion of the first surface 100a of the substrate 100. The second protective layer 108 is located between the first protective layer 106 and the upper electrode 102, whereby the second protective layer 108 can strengthen the isolation between the first semiconductor structure 111 and the upper electrode 102 to prevent electrical connection between the two.

In some embodiments, the substrate 100 is, for example, a silicon substrate, a nitride-based semiconductor substrate, a silicon carbide substrate, or a gallium arsenide substrate. In one embodiment, the substrate 100 may be further processed by patterning, for example, the substrate 100 may be patterned to form a rough surface, but the present invention is not limited thereto. In detail, the first surface 100a and the second surface 100b of the substrate 100 of the present embodiment have different roughnesses, the second surface 100b has a roughening structure and the roughness is greater than the first surface 100a, the substrate 100 is connected to the semiconductor stack 110 by the first surface 100a, and is connected to the lower electrode 104 by the second surface 100b. The roughening structure can increase the adhesion between the substrate 100 and the lower electrode 104. In one embodiment, the substrate 100 includes a semiconductor material containing nitrogen, such as gallium nitride (GaN) or other suitable materials. The upper surface 100a of the substrate 100 includes a (0001) plane, a (000-1) plane, a (10-10) plane, a (11-20) plane, a (10-14) plane, a (10-15) plane, and a (11-24) plane, and the (0001) plane is preferably used as the epitaxial growth surface of the semiconductor stack 110. The thickness of the substrate 100 may be between 50 μm and 500 μm.

In addition, a transparent conductive layer (not shown) may be selectively disposed on the contact layer 115 to distribute the current more evenly in the semiconductor device 10. The transparent conductive layer covers a portion of the first protective layer 106. The material of the transparent conductive layer can be indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), zinc oxide (ZnO), indium caesium oxide (ICO), indium tungsten oxide (IWO), indium titanium oxide (ITiO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum zinc oxide (GAZO) or a combination of the above materials, or a transparent metal layer (e.g., aluminum, nickel, gold with a thickness of less than 500 angstroms).

In some embodiments, the material of the upper electrode 102 may include chromium (Cr), aluminum (Al), palladium (Pd), platinum (Pt), nickel (Ni), gold (Au), titanium (Ti), tungsten (W), any combination thereof, or other suitable conductive materials. The material of the lower electrode 104 may include palladium (Pd), chromium (Cr), titanium (Ti), aluminum (Al), gold (Au), platinum (Pt), any combination thereof, or other suitable conductive materials, and may also be a composite material formed by multiple conductive materials.

The first protective layer 106 and/or the second protective layer 108 include oxides, nitrides, oxynitrides of silicon (Si), zirconium (Zr), aluminum (Al), or tantalum (Ta), or a single layer of the aforementioned materials or a multilayer of any two or more of the aforementioned materials. The thickness of the first protective layer 106 and/or the second protective layer 108 is not particularly limited, as long as the thickness can reduce or prevent the externally injected current from directly flowing from the upper electrode 102 to the semiconductor stack 110 and achieve a protective effect on the semiconductor stack 110.

FIG. 4 is a cross-sectional schematic diagram of a laser diode device 2 according to an embodiment of the present disclosure. The laser diode device 2 includes a heat sink 21, a first pin 22a and a second pin 22b, a fixing base 23, a primary fixing base 231, a laser diode chip 24, and a metal cover 27. The first pin 22a and the second pin 22b are disposed on the back of the heat sink 21. The fixing base 23 is protrudingly disposed on the surface of the heat sink 21 and is connected to the second pin 22b connected to the ground (GND). The secondary fixing base 231 is disposed on the inner side of the fixing base 23 and provides a connection for the laser diode chip 24. The metal cover 27 further includes a glass window 271 disposed on the top surface thereof, and the bottom edge of the metal cover 27 is connected to the top of the heat sink 21. The laser diode chip 24 may include a semiconductor element 10 according to an embodiment of the present disclosure, but the present disclosure is not limited thereto.

In summary, although the embodiments have been disclosed above, they are not intended to limit the present disclosure. Those with ordinary knowledge in the technical field to which the present disclosure belongs can make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be determined by the scope of the attached patent application.

10: semiconductor element 100: substrate 100a: first surface 100b: second surface 102: upper electrode 104: lower electrode 106: first protective layer 108: second protective layer 110: semiconductor stack 111: first semiconductor structure 111a: first sublayer 111b: second sublayer 1111: base 1112: ridge 112: second semiconductor structure 113: active structure 114: blocking layer 115: contact layer 116: first photoconductive layer 117: second photoconductive layer 2: laser diode device 21: heat sink 22a: First pin 22b: Second pin 23: Fixing seat 231: Second fixing seat 24: Laser diode chip 27: Metal cover 271: Glass window

FIG. 1 is a schematic cross-sectional view of a semiconductor device according to an embodiment of the present disclosure.

FIG. 2 is a schematic cross-sectional view of a semiconductor stack of a semiconductor device according to an embodiment of the present disclosure.

FIG. 3 is a secondary ion mass spectrum (SIMS) diagram of a semiconductor device according to an embodiment of the present disclosure.

FIG. 4 is a cross-sectional view of a laser diode device according to an embodiment of the present disclosure.

10: Semiconductor components

100: Substrate

100a: first surface

100b: Second surface

102: Upper electrode

104: Lower electrode

106: First protective layer

108: Second protective layer

110: Semiconductor stacking

111: First semiconductor structure

111a: First sublayer

111b: Second sublayer

1111: Base

1112: Spine

112: Second semiconductor structure

113: Active structure

Claims (10)

A semiconductor device comprises: a first semiconductor structure having a first conductivity type and including a first doping, a second doping and a third doping; a second semiconductor structure having a second conductivity type different from the first conductivity type; and an active structure located between the first semiconductor structure and the second semiconductor structure; wherein the doping concentration of the first doping is less than 3.5×10 ¹⁷ atoms/cm ³ , the ratio of the doping concentration of the third doping to the doping concentration of the second doping is greater than 5, and the first semiconductor structure contains aluminum. A semiconductor device as described in claim 1, wherein the first semiconductor structure has a first sublayer and a second sublayer, the first sublayer is closer to the active structure than the second sublayer, and the concentration of the third dopant in the first sublayer is less than the concentration of the third dopant in the second sublayer. A semiconductor device as described in claim 1 or 2, wherein a ratio of a doping concentration of the third doping to a doping concentration of the first doping in the first semiconductor structure is 25 to 100. A semiconductor element as described in claim 1 or 2, further comprising a blocking layer located between the first semiconductor structure and the active structure, the blocking layer comprising aluminum, and the aluminum in the first semiconductor structure has a first atomic percentage, and the aluminum in the blocking layer has a second atomic percentage greater than the first atomic percentage. The semiconductor device as described in claim 2 further comprises a blocking layer located between the first sublayer and the active structure, the blocking layer comprises the third dopant, and the concentration of the third dopant in the blocking layer is greater than the concentration of the third dopant in the first sublayer. A semiconductor device as described in claim 1 or 2, wherein the first doping is carbon. A semiconductor device as described in claim 1 or 2, wherein the second doping is hydrogen. A semiconductor device as described in claim 1 or 2, wherein the third doping is magnesium. The semiconductor element as described in claim 1 or 2 further includes an upper electrode, the first semiconductor structure includes a ridge and the upper electrode covers the ridge. A semiconductor element as described in claim 1 or 2, wherein the semiconductor light-emitting element is a laser element.

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