Method for Increasing Grain Size in Silicon and Germanium by Successive Doping
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
The presence of grain boundaries in semiconductors is often undesirable, but tolerated for reason of economy and ease of fabrication. Grain boundaries increase the resistivity of semiconductors by scattering majority carriers and by trapping dopants, by segregation, in an electrically inactive state. A technique is described for the migration of grain boundaries to produce polycrystalline semiconductors with exceptionally large grain size. The method of this invention is the alloying of semiconductors, specifically Si and Ge, to cause grain boundary migration. Two or more successive doping treatments used in the temperature range, 0.3Tm < T < 0.5Tm, where Tm is the absolute melting temperature of the semiconductor.