Hydrogen diffusion barrier for hybrid semiconductor growth

Abstract

Semiconductor devices and methods of fabricating semiconductor devices having a dilute nitride active layer and at least one semiconductor material overlying the dilute nitride active layer are disclosed. Hybrid epitaxial growth and the use of hydrogen diffusion barrier layers to minimize hydrogen diffusion into the dilute nitride active layer are used to fabricate high-efficiency multijunction solar cells and photonic devices. Hydrogen diffusion barriers can be formed through the use of layer thickness, composition, doping and/or strain.

1 . A method of fabricating a semiconductor device comprising a dilute nitride active layer, comprising:
 growing a dilute nitride active layer overlying a substrate using molecular beam epitaxy, the dilute nitride layer comprising:
 a dilute nitride material selected from GaNAs, GaInNAs, GaInNAsSb, GaInNAsBi, GaInNAsSbBi, GaNAsSb, GaNAsBi, and GaNAsSbBi, 
 a background doping concentration less than 5×10 16  cm −3 , and 
 a hydrogen-induced defect density less than the background doping density; 
   growing a hydrogen diffusion barrier region overlying the dilute nitride active layer using molecular beam epitaxy, wherein the hydrogen diffusion barrier region comprises a doped semiconductor layer, a dilute nitride semiconductor layer, a strained semiconductor layer, or a combination of any of the foregoing;   thermally annealing the substrate, the dilute nitride active layer, and the hydrogen diffusion barrier region; and   growing a semiconductor layer adjacent the hydrogen diffusion barrier region using metal-organic chemical vapor deposition.   
     
     
         2 . The method of  claim 1 , further comprising:
 after growing the dilute nitride active layer and before growing the hydrogen diffusion barrier region, growing one or more intervening semiconductor layers overlying the dilute nitride active layer using molecular beam epitaxy,   wherein growing the hydrogen diffusion barrier region comprises growing the hydrogen diffusion barrier region adjacent an uppermost intervening semiconductor layer.   
     
     
         3 . The method of  claim 2 , wherein growing the one or more intervening semiconductor layers comprises growing (In)GaAs, (Al)GaAs, or both. 
     
     
         4 . The method of  claim 1 , wherein thermally annealing the substrate, the dilute nitride active layer, and the hydrogen diffusion barrier region comprises rapid thermal annealing. 
     
     
         5 . The method of  claim 1 , further comprising:
 after growing the semiconductor layer, thermally annealing the substrate, the dilute nitride active layer, the hydrogen diffusion barrier region, and the semiconductor layer.   
     
     
         6 . The method of  claim 1 , wherein growing the hydrogen diffusion barrier comprises doping the doped semiconductor layer with a dopant selected from C, Be, Zn, Si, Se, Te, and a combination of any of the foregoing. 
     
     
         7 . The method of  claim 1 , wherein the doped semiconductor layer comprises a doping level between 1×10 17  cm −3  and 2×10 20  cm −3 . 
     
     
         8 . The method of  claim 1 , wherein the dilute nitride semiconductor layer comprises GaAsN, AlGaAsN, GaInAsN, GaN, AN, AlNSb, GaNSb, GaInNAsSb, GaNBi or AlNBi. 
     
     
         9 . The method of  claim 1 , wherein the dilute nitride active material comprises Ga 1-x In x N y As 1-y-z Sb z ,
 wherein:
 0≤x≤0.24, 0.001≤y≤0.07, and 0.001≤z≤0.2; 
 0.08≤x≤0.24, 0.02≤y≤0.05, and 0.001≤z≤0.02; 
 0.07≤x<0.18, 0.025≤y≤0.04, and 0.001≤z≤0.03; or 
 0≤x≤0.4, 0<y≤0.07, and 0<z≤0.04. 
   
     
     
         10 . The method of  claim 1 , wherein the strained semiconductor layer is a strained superlattice structure (SLS). 
     
     
         11 . The method of  claim 1 , wherein the hydrogen diffusion barrier region comprises an aluminum-containing layer. 
     
     
         12 . The method of  claim 1 , further comprising:
 growing a nucleation layer and at least a portion of a buffer layer using metal-organic chemical vapor deposition.   
     
     
         13 . The method of  claim 12 , further comprising:
 growing another portion of the buffer layer using molecular beam epitaxy.   
     
     
         14 . The method of  claim 1 , further comprising:
 growing a second semiconductor layer overlying the semiconductor layer using metal-organic chemical vapor deposition.   
     
     
         15 . The method of  claim 1 , wherein growing the semiconductor layer comprises growing a Distributed Bragg Reflector. 
     
     
         16 . The method of  claim 1 , further comprising:
 growing a protective layer overlying the hydrogen diffusion barrier region using molecular beam epitaxy.   
     
     
         17 . The method of  claim 1 , wherein the hydrogen diffusion barrier region comprises AlAs, AlGaAs, GaAs, InAs, InGaAs, AlInAs, InGaP, AlInGaP, InGaP, GaP, InP, AlP, AlInP, or AlInGaAs. 
     
     
         18 . The method of  claim 1 , further comprising:
 transferring the semiconductor device after growing the hydrogen diffusion barrier region and before growing the semiconductor layer, wherein the transferring comprises transferring the semiconductor device in atmospheric pressure.   
     
     
         19 . The method of  claim 1 , further comprising:
 transporting the semiconductor device after growing the hydrogen diffusion barrier region and before growing the semiconductor layer, wherein the transporting comprises transporting the semiconductor device in vacuum.   
     
     
         20 . The method of  claim 1 , wherein the molecular beam epitaxy is performed in a molecular beam epitaxy system and the metal-organic chemical vapor deposition is performed in a metal-organic chemical vapor deposition system, further comprising:
 growing a protective layer before transferring or transporting the semiconductor device from the molecular beam epitaxy system to the metal-organic chemical vapor deposition system.