ONR-funded researchers at Cornell University recently announced a breakthrough in creating a universal substrate for semiconductors. By bonding a thin film of material onto a bulk substrate at a misaligned angle, a pure, defect-free single crystal of almost any material can be grown on any substrate. This discovery could give rise to an entire new generation of electronics. Manufacturing semiconductors has always been limited by the fact that a thin film must be deposited on a substrate of exactly the same structure or defects arise that inhibit function. The Cornell technique slightly rotates the thin film as much as 15 percent and bonds it to the thicker bottom layer. The researchers call the bonded region the "twist boundary" and the misaligned layers a "compliant substrate." The Cornell team demonstrated the technique with thick, pure crystal layers of indium gallium phosphide, gallium antimonide and indium antimonide. A paper describing these results titled "Lattice Engineered Compliant Substrate for Defect-free Heteroepitaxial Growth" appears in the March 31 issue of Applied Physics Letters.
Applied Physics Letters