Growth of large-area, single-crystalline AlN substrates (Subtopic A: Electronic Materials)

Teh objective of the proposed work is to develop a process for the fabrication large-area aluminum nitride (AlN) wafers of up to 2" in diameter for III-nitride substrate applications. The growth process is based on a sublimation technique that utilizes adequately prepared SiC wafers as large-area seeds. A multi-step process developed in Phase I will be upscaled to larger area deposition, and will be tailored to (1) avoid SiC decomposition, (2) prepare the SiC seed surface for subsequent AlN deposition, and (3) to greatly reduce stress in the AlN single crystal. Boules will be oriented and cut into single crystalline wafers, which will be polished and, at later stages in the project, re-used as seeds.