DILUTE NITRIDE DEVICES WITH ACTIVE GROUP IV SUBSTRATE AND CONTROLLED DOPANT DIFFUSION AT THE NUCLEATION LAYER-SUBSTRATE INTERFACE
Semiconductor devices having an antimony-containing nucleation layer between a dilute nitride material and an underlying substrate are disclosed. Dilute nitride-containing multijunction solar cells incorporating (Al)InGaPSb/Bi nucleation layers exhibit high efficiency.
1 . A semiconductor device, comprising:
a substrate, wherein the substrate comprises GaAs, (Si,Sn)Ge or Si; and
a nucleation layer overlying the substrate, wherein the nucleation layer comprises a III-V alloy, wherein the group V element comprises Sb, Bi, or a combination thereof.
2 . The semiconductor device of claim 1 , wherein the substrate comprises Ga-doped Ge.
3 . The semiconductor device of claim 1 , wherein the III-V alloy comprises (Al)InGaPSb/Bi.
4 . The semiconductor device of claim 1 , wherein the nucleation layer is lattice matched to the substrate.
5 . The semiconductor device of claim 1 , wherein the nucleation layer is n-doped and the substrate is p-doped.
6 . The semiconductor device of claim 1 , wherein the III-V alloy comprises from 0.2% to 10% Sb, Bi, or a combination thereof, where % is based on elemental content.
7 . The semiconductor device of claim 1 , wherein a region of the substrate within a range from 10 nm to 50 nm adjacent the nucleation layer comprises Sb or Bi.
8 . The semiconductor device of claim 1 , further comprising at least one dilute nitride semiconductor layer overlying the nucleation layer, wherein the at least one dilute nitride semiconductor layer comprises:
at least one group III element comprising Al, Ga, In, or a combination of any of the foregoing; and
at least one group V element comprising N, P, As, Sb, Bi, or a combination of any of the foregoing.
9 . The semiconductor device of claim 8 , wherein the at least one dilute nitride semiconductor layer comprises GaInNAs, GaInNAsSb, GaInNAsBi, GaInNAsSbBi, GaNAs, GaNAsSb, GaNAsBi, or GaNAsSbBi.
10 . The semiconductor device of claim 1 , wherein the semiconductor device comprises a multijunction photovoltaic cell.
11 . The semiconductor device of claim 10 , wherein the multijunction solar cell exhibits an efficiency greater than 30%, measured with a 1 sun AM0 standard space spectrum at a junction temperature of 25° C.
12 . The semiconductor device of claim 11 , wherein,
the substrate comprises Ga-doped germanium;
the nucleation layer comprises (Al)InGaPSb, (Al)InGaPBi, or (Al)InGaPSbBi; and
the at least one dilute nitride subcell comprises GaInNAsSb, GaInNAsBi, or GaInNAsSbBi.
13 . The semiconductor device of claim 11 , further comprising:
a (Al,In)GaAs subcell overlying the at least one dilute nitride subcell; and
a (Al,In)GaP subcell overlying the (Al,In)GaAs subcell.
14 . The semiconductor device of claim 1 , comprising an emitter layer at an interface between the nucleation layer and the substrate, wherein,
the substrate is a p-type substrate; and
the emitter layer comprises a group V element selected from P, Sb, Bi, or a combination of any of the foregoing.
15 . The semiconductor device of claim 1 , wherein,
the substrate is a p-type substrate; and
diffusion of a p-type dopant into the p-type substrate is attenuated within the first 50 nm from the nucleation layer.
16 . The semiconductor device of claim 1 , wherein a Ga concentration within a range of 50 nm to 200 nm from the interface with the nucleation layer is constant.
17 . The semiconductor device of claim 1 , wherein,
the substrate comprises germanium Ge; and
the substrate comprises antimony Sb in a region adjacent the nucleation layer.
18 . The semiconductor device of claim 1 , wherein the III-V alloy comprises (Al)InGaPSb/Bi.
19 . A solar energy power system comprising at least one multijunction photovoltaic cell of claim 10 .
20 . A method of fabricating a semiconductor device, comprising:
growing a nucleation layer on a substrate, wherein the nucleation layer comprises a III-V alloy, wherein the group V element comprises Sb, Bi, or a combination thereof; and
growing at least one semiconductor layer on the nucleation layer.
21 . The method of claim 20 , wherein,
the substrate comprises Ge; and
the III-V alloy comprises (Al)InGaPSb/Bi.
22 . The method of claim 20 , wherein the at least one semiconductor layer comprises a dilute nitride alloy.
23 . A semiconductor device fabricated using the method of claim 20 .