AlGan polarized ultraviolet photoelectric detector and manufacturing method thereof

Abstract

The invention discloses an AlGan material-based ultraviolet photoelectric detector structure and a manufacturing method thereof, which are mainly used for solving the problem of the dependence on a P-type doping material in the prior art. A detector comprises a substrate (1), a transition layer (2), a GaN buffer layer (3), an aluminum component gradual change AlGaN layer (4) and an active layer (5) from bottom to top, wherein the aluminum component gradual change AlGaN layer (4) is partitioned into an upper layer and a lower layer; the thickness of the lower layer is 20-30 nanometers, and thecontent of an aluminum component increases from 0 percent to 80-100 percent; the thickness of the upper layer is 10-20 nanometer, and the content of the aluminum component is 0-80 percent; the left upper side of the aluminum component gradual change AlGaN layer (4) is covered by the active layer (5); a bottom ohmic contact (7) is deposited on the right upper side of the aluminum component gradualchange AlGaN layer (4); a gap (8) is formed between the ohmic contact and the active region; the active region (5) consists of an AlGaN material with the aluminum component content of 0-80 percent; the thickness of the active region (5) is 50-100 nanometers; and a surface ohmic contact electrode (7) is deposited on the surface of the active region. The detector structure has the advantages of capability of automatically working in a photovoltaic mode, high high-frequency characteristic and small dark current, and can be applied to optical signal detection in ultraviolet wavebands between 226 nanometers and 363 nanometers.

Description

technical field

[0001] The invention belongs to the technical field of microelectronics, and in particular relates to an AlGaN ultraviolet photodetector, which can be used for optical signal detection in the 226-363nm ultraviolet band. Background technique

[0002] A semiconductor photodetector is a detector that changes the electrical properties of semiconductor materials by receiving light wave irradiation, thereby realizing the detection and resolution of targets. Changing the material and structural parameters of the semiconductor used can tune the range of response wavelengths. Those whose response wavelength is in the ultraviolet band are called semiconductor ultraviolet photodetectors. With the extensive use of microelectronic integrated circuit technology in aerospace, the original gas-phase and liquid-phase ultraviolet detectors are gradually replaced by this solid-state detector. The European Space Agency ESA's Solar Obiter program is ready to be realized in 2015...

Examples

Embodiment 1

[0030] Step 1, epitaxially grow transition layer 2 on substrate 1, such as image 3 a.

[0031] Using metal-organic chemical vapor deposition technology, grow an AlN transition layer 2 with a thickness of 10nm on the sapphire substrate 1 to release the stress caused by lattice mismatch. The growth process conditions are as follows: temperature is 990°C, pressure is 122 Torr, the flow rate of hydrogen gas is 4400 sccm, the flow rate of ammonia gas is 4400 sccm, and the flow rate of aluminum source is 6 μmol / min.

[0032] Step 2, depositing a GaN buffer layer 3 on the transition layer 2, such as image 3 b.

[0033] Using metal-organic chemical vapor deposition technology, a GaN buffer layer 3 with a thickness of 2 μm is grown on the transition layer 2. The GaN surface is required to be flat and there is no stress accumulation caused by lattice mismatch. The process conditions are: the temperature is 990°C , the pressure is 122 Torr, the flow rate of hydrogen gas is 4400 sccm, ...

Embodiment 2

[0043] Step 1, epitaxially grow transition layer 2 on substrate 1, such as image 3 a.

[0044] A buffer layer 2 made of AlN with a thickness of 5nm is grown on a silicon carbide substrate 1 by metal-organic chemical vapor deposition technology to release the stress caused by lattice mismatch. Process conditions: temperature is 990°C, pressure is 122Torr, hydrogen The flow rate is 4400 sccm, the flow rate of ammonia gas is 4400 sccm, and the flow rate of aluminum source is 6 μmol / min;

[0045] Step 2, depositing a GaN buffer layer 3 on the transition layer 2, such as image 3 b.

[0046] This step is the same as Step 2 of Embodiment 1.

[0047] Step 3, making an aluminum composition graded AlGaN layer 4 on the barrier layer 3, such as image 3 c.

[0048] Using metal-organic chemical vapor deposition technology, 25nm aluminum composition graded AlGaN is first deposited on the GaN buffer layer 3, and its aluminum composition increases from 0% to 90%. The process conditions...

Embodiment 3

[0056] Step 1, epitaxially grow transition layer 2 on substrate 1, such as image 3 a.

[0057] Using metal-organic chemical vapor deposition technology, first grow a 5nm thick AlN layer on the silicon substrate 1, the process conditions are: temperature 1040°C, pressure 100Torr, hydrogen flow rate 4400sccm, ammonia flow rate 4400sccm, aluminum source flow rate 6μmol / min; then grow 15 cycles of AlGaN / GaN superlattice, the thickness of the GaN potential well is 5nm, the aluminum composition of the AlGaN barrier layer is 20%, and the thickness is also 5nm. Process conditions: temperature 1040°C, pressure 100 Torr, hydrogen flow rate 4400 sccm, ammonia gas flow rate 4400 sccm, gallium source flow rate 120 μmol / min, aluminum source flow rate 1.2 μmol / min when growing AlGaN,

[0058] Step 2, depositing a GaN buffer layer 3 on the transition layer 2, such as image 3 b.

[0059] It is the same as Step 2 of Embodiment 1.

[0060] Step 3, making an aluminum composition graded AlGa...

technical field

[0001] The invention belongs to the technical field of microelectronics, and in particular relates to an AlGaN ultraviolet photodetector, which can be used for optical signal detection in the 226-363nm ultraviolet band. Background technique

[0002] A semiconductor photodetector is a detector that changes the electrical properties of semiconductor materials by receiving light wave irradiation, thereby realizing the detection and resolution of targets. Changing the material and structural parameters of the semiconductor used can tune the range of response wavelengths. Those whose response wavelength is in the ultraviolet band are called semiconductor ultraviolet photodetectors. With the extensive use of microelectronic integrated circuit technology in aerospace, the original gas-phase and liquid-phase ultraviolet detectors are gradually replaced by this solid-state detector. The European Space Agency ESA's Solar Obiter program is ready to be realized in 2015...

Examples

Embodiment 1

[0030] Step 1, epitaxially grow transition layer 2 on substrate 1, such as image 3 a.

[0031] Using metal-organic chemical vapor deposition technology, grow an AlN transition layer 2 with a thickness of 10nm on the sapphire substrate 1 to release the stress caused by lattice mismatch. The growth process conditions are as follows: temperature is 990°C, pressure is 122 Torr, the flow rate of hydrogen gas is 4400 sccm, the flow rate of ammonia gas is 4400 sccm, and the flow rate of aluminum source is 6 μmol / min.

[0032] Step 2, depositing a GaN buffer layer 3 on the transition layer 2, such as image 3 b.

[0033] Using metal-organic chemical vapor deposition technology, a GaN buffer layer 3 with a thickness of 2 μm is grown on the transition layer 2. The GaN surface is required to be flat and there is no stress accumulation caused by lattice mismatch. The process conditions are: the temperature is 990°C , the pressure is 122 Torr, the flow rate of hydrogen gas is 4400 sccm, ...

Embodiment 2

[0043] Step 1, epitaxially grow transition layer 2 on substrate 1, such as image 3 a.

[0044] A buffer layer 2 made of AlN with a thickness of 5nm is grown on a silicon carbide substrate 1 by metal-organic chemical vapor deposition technology to release the stress caused by lattice mismatch. Process conditions: temperature is 990°C, pressure is 122Torr, hydrogen The flow rate is 4400 sccm, the flow rate of ammonia gas is 4400 sccm, and the flow rate of aluminum source is 6 μmol / min;

[0045] Step 2, depositing a GaN buffer layer 3 on the transition layer 2, such as image 3 b.

[0046] This step is the same as Step 2 of Embodiment 1.

[0047] Step 3, making an aluminum composition graded AlGaN layer 4 on the barrier layer 3, such as image 3 c.

[0048] Using metal-organic chemical vapor deposition technology, 25nm aluminum composition graded AlGaN is first deposited on the GaN buffer layer 3, and its aluminum composition increases from 0% to 90%. The process conditions...

Embodiment 3

[0056] Step 1, epitaxially grow transition layer 2 on substrate 1, such as image 3 a.

[0057] Using metal-organic chemical vapor deposition technology, first grow a 5nm thick AlN layer on the silicon substrate 1, the process conditions are: temperature 1040°C, pressure 100Torr, hydrogen flow rate 4400sccm, ammonia flow rate 4400sccm, aluminum source flow rate 6μmol / min; then grow 15 cycles of AlGaN / GaN superlattice, the thickness of the GaN potential well is 5nm, the aluminum composition of the AlGaN barrier layer is 20%, and the thickness is also 5nm. Process conditions: temperature 1040°C, pressure 100 Torr, hydrogen flow rate 4400 sccm, ammonia gas flow rate 4400 sccm, gallium source flow rate 120 μmol / min, aluminum source flow rate 1.2 μmol / min when growing AlGaN,

[0058] Step 2, depositing a GaN buffer layer 3 on the transition layer 2, such as image 3 b.

[0059] It is the same as Step 2 of Embodiment 1.

[0060] Step 3, making an aluminum composition graded AlGa...

Images