HIGH GROWTH RATE DEPOSITION FOR GROUP III/V MATERIALS
Aspects of the disclosure relate to processes for epitaxial growth of III-V compound of (Al)GaInP material at high rates, such as about 8 μm/hr, 10 μm/hr, 20 μm/hr, 30 μm/hr, 40 μm/hr, and 8-120 μm/hr deposition rates. The high growth-rate deposited (Al)InGaP materials or films may be utilized in solar, semiconductor, or other electronic device applications. The Group III/V materials may be formed or grown on a sacrificial layer disposed on or over the support substrate during a chemical vapor deposition process. Subsequently, the Group III/V materials may be removed from the support substrate during an epitaxial lift off (ELO) process. The Group III/V materials are thin films of epitaxially grown layers containing gallium aluminum indium phosphide, gallium indium phosphide, derivatives thereof, alloys thereof, or combinations thereof.
1 . A method for forming a semiconductor material on a wafer, comprising:
heating a wafer to a deposition temperature in a range between 550° C. and 900° C. within a processing system;
exposing the wafer to a deposition gas comprising a gallium precursor gas, indium precursor gas and phosphine at a total pressure in a range between 20 Torr and 1000 Torr; and
depositing one or more layers having InGaP on the wafer at a deposition rate selected from the group consisting of 8 μm/hr, 10 μm/hr, 20 μm/hr, 30 μm/hr, and a range of 8-120 μm/hr deposition rates,
wherein multiple layers, including the one or more layers, form an InGaP cell.
2 . The method of claim 1 , wherein the InGaP cell is a metamorphic structure where the one or more InGaP layers are grown mismatched to the wafer, wherein the wafer is a GaAs substrate.
3 . The method of claim 1 , wherein the InGaP has a range of compositions represented by In x Ga 1-x P with x being the composition of indium, wherein the indium composition is in a range between 30% to 70% when the one or more InGaP layers are mismatched to the wafer and the wafer is a GaAs substrate, and wherein the indium composition is 50%+/−4% when the one or more InGaP layers are lattice-matched to GaAs.
4 . The method of claim 1 , wherein the InGaP cell is part of an optoelectronic device or an electronic device.
5 . The method of claim 4 , wherein the optoelectronic device includes a light-emitting diode (LED), a laser, a transistor-laser, a photodetector, or a photovoltaic, including a solar cell.
6 . The method of claim 4 , wherein the electronic device is a transistor and the transistor is one of a heterojunction bipolar transistor (HBT), a high electron mobility transistor (HEMT), a quantum well field effect transistor (QWFET), or a pseudomorphic HEMT (pHEMT).
7 . The method of claim 1 , wherein the gallium precursor gas and the indium precursor gas includes one or more of TMIn, TEIn, TMGa, TEGa, PH 3 , or TBP (tert-butylphosphine).
8 . The method of claim 1 , wherein for the 8-120 μm/hr deposition rates the range of the deposition temperature is between 550° C. and 900° C.
9 . The method of claim 1 , wherein the deposition gas further comprises a carrier gas comprising a mixture of hydrogen and argon.
10 . The method of claim 1 , wherein the InGaP cell is deposited over a sacrificial layer having a thickness between 1 nm and 200 nm, the sacrificial layer being disposed over a buffer layer, the buffer layer having a thickness in a range of 50 nm to 2000 nm, and the buffer layer being disposed over the wafer.
11 . The method of claim 10 , wherein the sacrificial layer is made of one of AlAs, AlInP, AlGaAs, AlInGaP, or InGaP.
12 . The method of claim 1 , wherein:
the multiple layers form an n-type InGaP stack and a p-type InGaP stack,
the n-type InGaP stack having an emitter layer disposed on or over a first passivation layer, the first passivation layer being disposed on or over a first contact layer, and
the p-type InGaP stack having a second contact layer disposed on or over a second passivation layer, the second passivation layer being disposed on or over an absorber layer.
13 . The method of claim 1 , wherein the InGaP cell forms an n-on-p solar cell, a p-on-n solar cell, an n-i-p solar cell, or a p-i-n solar cell.
14 . The method of claim 1 , wherein the InGaP cell is a front-junction device or a rear-junction device.
15 . The method of claim 1 , wherein the InGaP cell is a front-junction solar cell or a rear-junction solar cell.
16 . The method of claim 1 , wherein the InGaP cell includes one or more p-n junctions, and at least one of the one or more p-n junctions is a homojunction with InGaP on both sides of the junction.
17 . The method of claim 1 , wherein the InGaP cell includes one or more p-n junctions, and at least one of the one or more p-n junctions is a heterojunction with InGaP on one side and AlGaInP, AlGaAs, or AlInP on the other side, wherein the AlGaInP, AlGaAs, or AlInP is deposited at a deposition rate selected from the group consisting of 8 μm/hr, 10 μm/hr, 20 μm/hr, 30 μm/hr, and a range of 8-120 μm/hr deposition rates.
18 . The method of claim 1 , wherein the InGaP cell includes a graded junction and at least one of the one or more layers having InGaP is part of the graded junction.
19 . The method of claim 1 , wherein the range of the deposition temperature is between 600° C. and 800° C.
20 . The method of claim 1 , wherein the range of the total pressure is selected from the group consisting of:
between 20 Torr and 760 Torr,
between 50 Torr and 450 Torr, and
between 100 Torr and 250 Torr.
21 . The method of claim 1 , wherein the method is performed as part of a metal organic chemical vapor deposition (MOCVD) process that uses reactors with or without a showerhead configuration.
22 . The method of claim 1 , wherein a bubbler temperature for the indium precursor gas is in the range of 15° C. to 60° C.
23 . The method of claim 1 , wherein the deposition rate under V/III ratios of 1 to 300.
24 . A method of forming a cell, comprising:
heating a substrate comprising gallium and arsenic to a temperature in a range between 550° C. and 900° C. within a processing system;
exposing the substrate to a deposition gas comprising a gallium precursor gas and arsine;
depositing an n-type contact layer comprising gallium and arsenic over the substrate, the n-type contact layer having a thickness of 100 nm or less;
depositing a first passivation layer comprising one or more of the following elements: gallium, indium, aluminum, and phosphorous over the substrate, the first passivation layer having a thickness of 100 nm or less;
depositing an n-type or p-type absorber layer comprising one or more of the following elements: gallium, indium, aluminum and phosphorous over the substrate;
depositing a second passivation layer comprising one or more of the following elements: indium, gallium, alumnium and phosphorous over the substrate, the second passivation layer having a thickness of 2000 nm or less; and
depositing a p-type contact layer comprising one or more of the following elements: aluminum, gallium, and arsenic over the substrate, the p-type contact layer having a thickness of 2000 nm or less,
wherein each of the n-type contact layer, the first passivation layer, the n-type or p-type absorber layer, the n-type or p-type emitter layer, the second passivation layer, and the p-type contact layer is deposited at a deposition rate selected from the group consisting of 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and a range of 8-120 μm/hr deposition rates.
25 . The method of claim 24 , wherein for the 8-120 μm/hr deposition rates the range of the deposition temperature is between 550° C. and 900° C.
26 . The method of claim 24 , further comprising:
depositing a sacrificial layer comprising aluminum and arsenic over the substrate at a deposition rate selected from the group consisting of 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 μm/hr deposition rates, the sacrificial layer having a thickness of 200 nm or less;
depositing the n-type contact layer over the sacrificial layer;
depositing the first passivation layer over the n-type contact layer;
depositing the n-type or p-type absorber layer over the first passivation layer;
depositing the second passivation layer over the n-type of p-type absorber layer; and
depositing the p-type contact layer over the second passivation layer.
27 . The method of claim 26 , further comprising:
depositing a buffer layer comprising gallium and arsenic on the substrate at a deposition rate selected from the group consisting of a 30 μm/hr deposition rate, a 40 μm/hr deposition rate, a 50 μm/hr deposition rate, a 55 μm/hr deposition rate, and a 60 μm/hr deposition rate or greater, the buffer layer having a thickness in a range between 50 nm and 2000 nm; and
depositing the sacrificial layer over the buffer layer.
28 . The method of claim 24 , further comprising:
depositing a sacrificial layer comprising aluminum and arsenic over the substrate at a deposition rate selected from the group consisting of 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 μm/hr deposition rates, the sacrificial layer having a thickness of 200 nm or less.
29 . The method of claim 28 , further comprising:
depositing a buffer layer comprising gallium and arsenic on the substrate at a deposition rate selected from the group consisting of 30 μm/hr, 40 μm/hr, 50 μm/hr, 55 μm/hr, 60 μm/hr, 70 μm/hr, 80 μm/hr, and 90-120 μm/hr deposition rates, the buffer layer having a thickness in a range between 50 nm and 2000 nm; and
depositing the sacrificial layer over the buffer layer.
30 . The method of claim 24 , wherein exposing the substrate to a deposition gas further comprises:
exposing the substrate to a total pressure of 450 Torr or less, or
exposing the substrate to a total pressure of at least 780 Torr.
31 . The method of claim 24 , further comprising depositing an n-type or p-type emitter layer having a thickness of 2000 nm or less.