Papers by Author: Daisuke Nakamura

Abstract: The detailed properties of the dislocations of SiC crystals were analyzed using ultrahigh-quality substrates manufactured by RAF (repeated a-face) growth method by means of bulk X-ray topography. From this analysis, we could reveal the detailed features of one type of basal plane dislocations and two types of threading dislocations. The basal plane dislocations were screw type with Burgers vector were parallel to <11-20> direction. One of the threading dislocations was mixed type close to screw dislocation parallel to the growth direction with Burgers vector of 1c+na (n=0, 1, 2, …). Another was the edge type parallel to the c-axis, which was lying between two basal plane dislocations. Moreover, these dislocations were found to be connecting with each other, constituting large network structures.

Abstract: Recent reports on the impact of elementary dislocations on device performance and reliability suggest not only micropipe defects but also dislocations should be reduced or eliminated perfectly. This paper presents bulk growth process for reduction of the dislocations, and quality of the crystals grown by the process. Etch pit density of the best crystals grown by the process was lower by three orders of magnitude than that of conventional crystals. Moreover, large diameter crystals (>2”) with low dislocation density were successfully grown by the process.