SBIR-STTR Award

The objective of this proposal is to demonstrate the feasibility of large-area aluminum nitride (AlN) wafers for III-nitride substrate applications. The growth strategy consists of growing single crystalline AlN on adequately prepared SiC templates using a sublimation process. We propose to employ a multi-step deposition process to (1) avoid SiC decomposition, (2) prepare the SiC seed surface for AlN growth, and (3) to greatly reduce stress in the overgrown, single crystalline AlN. The use of SiC templates is appealing due to the ability of instantly producing large area growth. In this project, the feasibility of the proposed growth process will be explored on 1" 6H-SiC wafers.

The 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.

Keywords:
aln substrate, aln single crystal, iii-nitride epitaxy, large-area substrate, bulk growth