Growth of Large Diameter Silicon Carbide Boules

Absence of low defect density large diameter (~100mm) silicon carbide (SiC) wafers is a major barrier for the commercial production of SiC based devices. This phase I program is aimed at demonstrating a novel technique that will significantly reduce themechanical stress in SiC during boule growth. In phase I, we will demonstrate that by the proposed method, a significant reduction in the mechnical stress is achieved in the growth of a 75 mm diameter 4H-SiC boule. Also, in Phase I, we will slice theboule into wafers, lap and polish the wafers, and provide comparison of mechanical stress between wafers produced by the proposed and conventional approaches. In Phase II, the technique will be refined to demonstrate the production of commercially viable4H-n SiC boules, 100 mm in diameter, with a significant reduction in mechanical stress compared to those achieved by the conventional method.With the proposed approach, three specific advantages are anticipated: (a) substantial improvement in the qualityof commercially available wafers due to a significant reduction in the density of defects, (b) improvement in the yield of good quality wafers, and (c) reduction in the cost of good quality wafers, which will stimulate the widespread commercialization ofSiC devices for power conditioning and switching and for RF and microwave applications.