A deep ultraviolet semiconductor light emitting element

Abstract

The present invention relates to the technical field of semiconductor optoelectronic devices, and in particular to a deep ultraviolet semiconductor light-emitting element, which comprises, from bottom to top, a substrate, a buffer layer, a first conductive semiconductor, a multi-quantum well, a conductive electron blocking layer, and a second conductive semiconductor, wherein the H concentration of the conductive electron blocking layer is 1E17-5E18cm ‑3 , O concentration is 1E17~1E18cm ‑3 By controlling the H / O content of the conductive electron blocking layer, the Al y Ga 1‑y The H / O content and ratio of the N material can effectively reduce the hole ionization energy of the Mg layer, improve the hole ionization efficiency, and increase the free hole carrier concentration after ionization to 1E18cm ‑3 above.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor optoelectronic devices, and in particular to a deep ultraviolet semiconductor light-emitting element. Background Art

[0002] The semiconductor light-emitting element has a wide adjustable wavelength range, high luminous efficiency, energy saving and environmental protection, a long service life of more than 100,000 hours, small size, strong designability and other factors; the semiconductor light-emitting element can be adjusted by adjusting the Al component, and the wavelength can be as short as the ultraviolet band of 200-350nm; the AlGaN material with high Al component (Al component greater than 40%) has low Al mobility and low lateral growth rate, and there is a large lattice mismatch and thermal mismatch between AlGaN and the sapphire substrate, resulting in the growth difficulty of the AlGaN material with high Al component (Al component greater than 40%) being much higher than that of GaN material and AlGaN material with low Al component (Al component less than 40%), and it is easy to produce cracks, unflattened, rough and other surface problems; at the same time, the hole ionization energy of the AlGaN with high Al component increases sharply with the increase of Al component, the hole ionization rate decreases with the increase of Al component, and the resistance value increases with the increase of Al component, resulting in the ionized free hole concentration of the electron blocking layer of the conventional deep ultraviolet semiconductor light-emitting element being lower than 1E17cm -3 . Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a deep ultraviolet semiconductor light-emitting element, which is suitable for high Al component Al by setting a conductive electron blocking layer and controlling the C / H / O content ratio. y Ga 1-y The C / H / O content and ratio of the N material can effectively reduce the hole ionization energy of the layer, improve the hole ionization efficiency and Mg impurity solubility, and increase the free hole carrier concentration after ionization.

[0004] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0005] The present invention provides a deep ultraviolet semiconductor light-emitting element, which comprises, from bottom to top, a substrate, a buffer layer, a first conductive semiconductor, a multi-quantum well, a conductive electron blocking layer, and a second conductive semiconductor, wherein the H concentration of the conductive electron blocking layer is 1E17-5E18cm -3 , C concentration is 1E16~1E18cm -3 , O is between 1E17~1E18cm -3 .

[0006] In a possible technical solution, the H concentration of the first conductive semiconductor is 1E17-1E18 cm -3, C concentration is 1E16~5E16cm -3 , O concentration is 5E16~5E17cm -3 ; The first conductive semiconductor is Al x Ga 1-x N material, Al component x is 40% to 100%.

[0007] In a possible technical solution, the multi-quantum well is a quantum well layer and a quantum barrier layer Al a In b Ga 1-a-b N / A c In d Ga 1-c-d N composed of a periodic quantum structure, the quantum well layer is Al a In b Ga 1-a-b The N and Al components a are 30-50%, the Al component c of the quantum barrier layer is 50-100%, the In components b and d of the quantum well layer and the quantum barrier layer are both 0-20%, and the emitted light is deep ultraviolet light between 200-350nm; the H concentration of the multi-quantum well is 5E17-1E18cm -3 , C concentration is 1E16~5E16cm -3 , O concentration is 5E16~5E17cm -3 .

[0008] In a possible technical solution, the H concentration of the second conductive semiconductor is 1E18-1E22cm -3 , C concentration is 1E17~1E21cm -3 , O concentration is 1E17~1E21cm -3 .

[0009] In a possible technical solution, the conductive electron blocking layer is a high Al component Al y Ga 1-y N material, Al component y is 55-100%.

[0010] In a possible technical solution, the Mg doping concentration of the conductive electron blocking layer is 5E18-5E20cm -3 .

[0011] In a possible technical solution, the Mg doping concentration of the second conductive semiconductor is 5E19-5E20cm -3 .

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] The first conductive semiconductor is Al x Ga 1-xN material, Al component x is 40% to 100%, by controlling the C / H / O concentration of the first conductive semiconductor suitable for high Al component, regulating the crystal morphology suitable for the first conductive semiconductor, reducing the lattice mismatch between the first conductive semiconductor and the buffer layer, reducing the generation of surface cracks, and reducing the surface cracks to within 1 mm from the edge; at the same time, the electron ionization efficiency of the first conductive semiconductor is improved, the electron ionization energy is reduced, the contact resistance of the semiconductor light-emitting element and the lateral expansion capacity of the current are reduced, so that the local current density is improved, the probability of local breakdown is reduced, and the anti-ESD capability is improved.

[0014] By controlling the C / H / O concentration of multi-quantum wells with high Al components, the non-radiative recombination centers of the multi-quantum wells are reduced, the quantum localization confinement effect of the multi-quantum wells is enhanced, the confinement effect of the electron-hole wave function is enhanced, and the radiative recombination efficiency of the multi-quantum wells and the quantum efficiency of the semiconductor light-emitting element are improved.

[0015] The conductive electron blocking layer is high Al component Al y Ga 1-y N material, the Al component y is 55-100%. The hole ionization energy of high Al component AlGaN decreases sharply with the increase of Al component, resulting in the ionized free hole concentration of the electron blocking layer of conventional deep ultraviolet semiconductor light-emitting elements being lower than 1E17cm -3 ; By controlling the C / H / O content of the conductive electron blocking layer, the Al y Ga 1-y The C / H / O content and ratio of the N material can effectively reduce the hole ionization energy of the layer, improve the hole ionization efficiency, and increase the free hole carrier concentration after ionization to 1E18cm -3 The Mg doping concentration of the conductive electron blocking layer is 5E18~5E20cm -3 , so that the C / H / O and Mg concentrations match each other, which can further improve the hole ionization efficiency and Mg impurity solubility.

[0016] By controlling the C / H / O concentration of the second conductive semiconductor, the hole ionization efficiency of the second conductive semiconductor can be improved, the hole ionization energy can be reduced, the resistance of the contact interface can be reduced, and the ohmic contact and lateral expansion capability of the current can be improved; the Mg doping concentration of the second conductive semiconductor is 5E19~5E20cm -3 . BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of a semiconductor light emitting element according to an embodiment of the present invention;

[0018] Figure 2 is a SIMS secondary ion mass spectrum of a semiconductor light emitting element according to an embodiment of the present invention;

[0019] Reference numerals: 100: substrate; 101: buffer layer; 102: first conductive type semiconductor; 103: multiple quantum well; 104: conductive type electron blocking layer; 105: second conductive type semiconductor. DETAILED DESCRIPTION

[0020] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0021] like Figure 1 As shown, the deep ultraviolet semiconductor light-emitting element of Example 1 of the present invention includes, from bottom to top, a substrate 100, a buffer layer 101, a first conductive semiconductor 102, a multi-quantum well 103, a conductive electron blocking layer 104 and a second conductive semiconductor 105. The substrate 100 is a substrate on which nitride semiconductor crystals can be epitaxially grown on the surface, and a substrate having a high transmittance (for example, the transmittance of the light is above 50%) for the wavelength range of light emitted by the semiconductor light-emitting element can be selected and used; for example, aluminum nitride, sapphire, GaN, etc. can be listed as the material of the substrate 100; buffer layer 101: The buffer layer 101 performs a buffer function. From the perspective of the buffer function, preferably, the buffer layer 101 is a single crystal structure, preferably contains Al, and particularly preferably contains AlN as a group III nitride, as a constituent of the buffer layer 1 The material of 01, as long as it is a III-group nitride compound semiconductor represented by the general formula AlGaInN, can be applied to the present invention, preferably GaAlN, preferably with an Al component of more than 50%; the first conductive semiconductor 102 and the second conductive semiconductor 105 can be an n-type semiconductor layer with an n-type conductivity; or a p-type semiconductor layer with a p-type conductivity; the buffer layer, the first conductive semiconductor, the multi-quantum well, the second conductive hole injection layer and the second conductive semiconductor are sequentially stacked on the substrate 100, and the stacked semiconductor layers are stacked by metal organic chemical vapor deposition (MOCVD), metal organic vapor phase epitaxy (MOVPE), molecular beam epitaxy (MBE) and hydride vapor phase epitaxy (HVPE); the H concentration of the conductive electron blocking layer is 1E17~5E18cm -3 , C concentration is 1E16~1E18cm -3 , O concentration is 1E17~1E18cm -3 The conductive electron blocking layer is a high Al component Al y Ga 1-y N material, the Al component y is 55-100%. The hole ionization energy of high Al component AlGaN decreases sharply with the increase of Al component, resulting in the ionized free hole concentration of the electron blocking layer of conventional deep ultraviolet semiconductor light-emitting elements being lower than 1E17cm-3 ; The H / O content can be controlled by controlling the pressure, temperature, MO source, flow rate and ratio of N2 / H2 / NH3 during the stacking process, and the C / H / O content of the conductive electron blocking layer can be controlled. The regulation is suitable for high Al component Al y Ga 1-y The C / H / O content and ratio of the N material can effectively reduce the hole ionization energy of the layer, improve the hole ionization efficiency, and increase the free hole carrier concentration after ionization to 1E18cm -3 Preferably, the Mg doping concentration of the conductive electron blocking layer is 5E18-5E20cm -3 , so that the C / H / O and Mg concentrations match each other, which can further improve the hole ionization efficiency and the solubility of Mg impurities; the Mg doping of this layer should not be too high or too low. Mg doped too high cannot be ionized to become a self-compensating center, but will reduce the concentration of free holes and the concentration of holes injected into the multi-quantum wells; if the Mg doping concentration is too low, the free hole concentration will be too low, which will also lead to a low concentration of holes injected into the multi-quantum wells.

[0022] As an improvement to the above technical solution, the H concentration of the first conductive semiconductor is 1E17-1E18 cm -3 , C concentration is 1E16~5E16cm -3 , O concentration is 5E16~5E17cm -3 , the first conductive semiconductor is Al x Ga 1-x N material, Al component x is 40% to 100%, by controlling the C / H / O concentration of the first conductive semiconductor suitable for high Al component, regulating the crystal morphology suitable for the first conductive semiconductor, reducing the lattice mismatch between the first conductive semiconductor and the buffer layer, reducing the generation of surface cracks, and reducing the surface cracks to within 1 mm from the edge; at the same time, the electron ionization efficiency of the first conductive semiconductor is improved, the electron ionization energy is reduced, the contact resistance of the semiconductor light-emitting element and the lateral expansion capacity of the current are reduced, so that the local current density is improved, the probability of local breakdown is reduced, and the anti-ESD capability is improved.

[0023] The multi-quantum well 102 is composed of a stacked structure formed by alternating well layers and barrier layers. Preferably, the multi-quantum well is composed of a quantum well layer and a quantum barrier layer Al a In b Ga 1-a-b N / A c In d Ga 1-c-d N composed of a periodic quantum structure, the quantum well layer is Al a In b Ga 1-a-bThe N and Al components a are 30-50%, the Al component c of the quantum barrier layer is 50-100%, the In components b and d of the quantum well layer and the quantum barrier layer are both 0-20%, and the emitted light is deep ultraviolet light between 200-350nm; the H concentration of the multi-quantum well is 5E17-1E18cm -3 , C concentration is 1E16~5E16cm -3 , O concentration is 5E16~5E17cm -3 ; By controlling the C / H / O concentration of the multi-quantum wells, the non-radiative recombination centers of the multi-quantum wells are reduced, the quantum localization confinement effect of the multi-quantum wells is enhanced, the confinement effect of the electron-hole wave function is enhanced, and the radiative recombination efficiency of the multi-quantum wells and the quantum efficiency of the semiconductor light-emitting elements are improved.

[0024] As an improvement to the above technical solution, the H concentration of the second conductive semiconductor is 1E18-1E22cm -3 , C concentration is 1E17~1E21cm -3 , O concentration is 1E17~1E21cm -3 By controlling the C / H / O concentration of the second conductive semiconductor, the hole ionization efficiency of the second conductive semiconductor can be improved, the hole ionization energy can be reduced, the resistance of the contact interface can be reduced, and the ohmic contact and lateral expansion capability of the current can be improved; preferably, the Mg doping concentration of the second conductive semiconductor is 5E19-5E20cm -3 ; The Mg doping of this layer should not be too high or too low. If the Mg doping is too high, the Mg cannot be ionized to become a self-compensation center, but will reduce the concentration of free holes and become a non-radiative recombination center to absorb light; if the Mg doping concentration is too low, the free hole concentration will be too low, the contact resistance will be large, and the current expansion will be poor.

[0025] Figure 2 This is a SIMS secondary ion mass spectrum of a semiconductor light-emitting element according to one specific embodiment of the present invention. The contents of elements such as C / H / O / Mg / Si / Al / Ga in each layer are all within the required range.

[0026] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A deep ultraviolet semiconductor light-emitting element, characterized in that: From bottom to top, it includes a substrate, a buffer layer, a first conductive semiconductor, a multi-quantum well, a conductive electron blocking layer, and a second conductive semiconductor. The H concentration of the first conductive semiconductor is 1E17-1E18cm -3 , C concentration is 1E16~5E16cm -3 , O concentration is 5E16~5E17cm -3 ; The first conductive semiconductor is Al x Ga 1-x N material, the Al component x is 40% to 100%; the conductive electron blocking layer is a high Al component Al y Ga 1-y N material, Al component y is 55-100%, H concentration is 1E17-5E18cm -3 , C concentration is 1E16~1E18cm -3 , O concentration is 1E17~1E18cm -3 .

2. The deep ultraviolet semiconductor light emitting element according to claim 1, characterized in that: The multi-quantum well is composed of a quantum well layer and a quantum barrier layer Al a In b Ga 1-a-b N / A c In d Ga 1-c-d N composed of a periodic quantum structure, the quantum well layer is Al a In b Ga 1-a- b The N and Al components a are 30-50%, the Al component c of the quantum barrier layer is 50-100%, the In components b and d of the quantum well layer and the quantum barrier layer are both 0-20%, and the emitted light is deep ultraviolet light between 200-350nm; the H concentration of the multi-quantum well is 5E17-1E18cm -3 , C concentration is 1E16~5E16cm -3 , O concentration is 5E16~5E17cm -3 .

3. The deep ultraviolet semiconductor light emitting element according to claim 1, characterized in that: The H concentration of the second conductive semiconductor is 1E18-1E22cm -3 , O concentration is 1E17~1E21cm -3 .

4. The deep ultraviolet semiconductor light emitting element according to claim 1, characterized in that: The Mg doping concentration of the conductive electron blocking layer is 5E18-5E20cm -3 .

5. The deep ultraviolet semiconductor light emitting element according to claim 1, characterized in that: The Mg doping concentration of the second conductive semiconductor is 5E19-5E20cm -3 .

6. The deep ultraviolet semiconductor light emitting element according to claim 5, characterized in that: The H / O content and ratio of the conductive electron blocking layer can effectively reduce the hole ionization energy of the layer, improve the hole ionization efficiency, and increase the free hole carrier concentration after ionization to 1E18cm -3 The above; the H / O and Mg concentrations in this layer match each other, which can further improve the hole ionization efficiency and the solubility of Mg impurities.

7. The deep ultraviolet semiconductor light emitting element according to claim 2, characterized in that: By regulating the H / O concentration of the first conductive semiconductor, the crystal morphology of the first conductive semiconductor can be regulated, the lattice mismatch between the first conductive semiconductor and the buffer layer can be reduced, and the generation of surface cracks can be reduced to within 1 mm from the edge; at the same time, the electron ionization efficiency of the first conductive semiconductor is improved, the electron ionization energy is reduced, the contact resistance of the semiconductor light-emitting element and the lateral expansion capacity of the current are reduced, so that the local current density is improved, the probability of local breakdown is reduced, and the ESD resistance is improved.

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