Semiconductor devices including substrate layers and overlying semiconductor layers having closely matching coefficients of thermal expansion, and related methods

Abstract

Embodiments relate to semiconductor structures and methods of forming semiconductor structures. The semiconductor structures include a substrate layer having a CTE that closely matches a CTE of one or more layers of semiconductor material formed over the substrate layer. In some embodiments, the substrate layers may comprise a composite substrate material including two or more elements. The substrate layers may comprise a metal material and/or a ceramic material in some embodiments.

What is claimed is: 
     
         1 . A semiconductor structure, comprising:
 a composite substrate layer;   a first semiconductor layer disposed over a surface of the composite substrate layer; and   at least one additional semiconductor layer epitaxially deposited over the first semiconductor layer on a side thereof opposite the composite substrate layer;   wherein the composite substrate layer exhibits a CTE closely matching a CTE of at least one of the first semiconductor layer and the at least one additional semiconductor layer.   
     
     
         2 . The semiconductor structure of  claim 1 , further comprising a metallic contact layer disposed between the composite substrate layer and the first semiconductor layer. 
     
     
         3 . The semiconductor structure of  claim 1 , wherein the composite substrate layer exhibits a CTE within about 5% of a CTE of at least one of the first semiconductor layer and the at least one additional semiconductor layer. 
     
     
         4 . The semiconductor structure of  claim 3 , wherein the composite substrate layer exhibits a CTE within about 2% of a CTE of at least one of the first semiconductor layer and the at least one additional semiconductor layer. 
     
     
         5 . The semiconductor structure of  claim 4 , wherein the composite substrate layer exhibits a CTE within about 1% of a CTE of at least one of the first semiconductor layer and the at least one additional semiconductor layer. 
     
     
         6 . The semiconductor structure of  claim 1 , wherein the composite substrate layer has an average thickness of at least about ten microns (10.0 μm). 
     
     
         7 . The semiconductor structure of  claim 6 , wherein the composite substrate layer has an average thickness of between about ten microns (10.0 μm) and about one hundred microns (100.0 μm). 
     
     
         8 . The semiconductor structure of  claim 7 , wherein the first semiconductor layer has an average thickness of about five hundred nanometers (500 nm) or less. 
     
     
         9 . The semiconductor structure of  claim 8 , wherein the first semiconductor layer has an average thickness of about one hundred nanometers (100 nm) or less. 
     
     
         10 . The semiconductor structure of  claim 1 , wherein the at least one additional semiconductor layer has an average total thickness of at least one hundred nanometers (100 nm). 
     
     
         11 . The semiconductor structure of  claim 10 , wherein the at least one additional semiconductor layer has an average total thickness of between about one micron (1.0 μm) and about one hundred microns (100.0 μm). 
     
     
         12 . The semiconductor structure of  claim 11 , wherein the first semiconductor layer comprises a semiconductor material selected from the group consisting of silicon, germanium, III-V semiconductor material, and II-VI semiconductor material. 
     
     
         13 . The semiconductor structure of  claim 11 , wherein the composite substrate layer comprises one of a metal-metal composite material, a ceramic-ceramic composite material, and a metal-ceramic composite material. 
     
     
         14 . The semiconductor structure of  claim 11 , wherein:
 at least one of the first semiconductor layer and the at least one additional semiconductor layer comprises gallium nitride (GaN); and   the composite substrate layer comprises tantalum (Ta) and tungsten (W).   
     
     
         15 . The semiconductor structure of  claim 14 , wherein the at least one additional semiconductor layer comprises gallium nitride (GaN). 
     
     
         16 . The semiconductor structure of  claim 15 , wherein the first semiconductor layer comprises silicon (Si). 
     
     
         17 . The semiconductor structure of  claim 14 , wherein each of the first semiconductor layer and the at least one additional semiconductor layer comprises gallium nitride (GaN). 
     
     
         18 . The semiconductor structure of  claim 1 , wherein:
 at least one of the first semiconductor layer and the at least one additional semiconductor layer comprises silicon (Si); and   the composite substrate layer comprises silicon oxide (SiO 2 ) and aluminum oxide (Al 2 O 3 ).   
     
     
         19 . The semiconductor structure of  claim 18 , wherein the at least one additional semiconductor layer comprises silicon (Si). 
     
     
         20 . The semiconductor structure of  claim 19 , wherein each of the first semiconductor layer and the at least one additional semiconductor layer comprises silicon (Si). 
     
     
         21 . The semiconductor structure of  claim 18 , wherein the composite substrate layer comprises about seventy five percent by volume silicon oxide (SiO 2 ) and about twenty five percent by volume aluminum oxide (Al 2 O 3 ). 
     
     
         22 . The semiconductor structure of  claim 1 , wherein:
 at least one of the first semiconductor layer and the at least one additional semiconductor layer comprises silicon carbide (SiC); and   the composite substrate layer comprises silicon oxide (SO 2 ) and aluminum oxide (Al 2 O 3 ).   
     
     
         23 . The semiconductor structure of  claim 22 , wherein each of the first semiconductor layer and the at least one additional semiconductor layer comprises silicon carbide (SiC). 
     
     
         24 . The semiconductor structure of  claim 22 , wherein the composite substrate layer comprises about forty nine percent by volume silicon oxide (SiO 2 ) and about fifty one percent by volume aluminum oxide (Al 2 O 3 ).