New high ohmic silicon carbide single crystals, useful as substrates in semiconductor components, have controlled, low content of sulfur as electrically active multiple donor component

摘要

In new high ohmic silicon carbide (SiC) single crystals (I), either: (a) the sulfur (S) content is lower than the content of electrically active defect sites (EADS's) obtained under equilibrium growth conditions; or (b) the S content is below the detection limit and the intrinsic EADS content is not more than the equilibrium content and corresponds to the content obtained under equilibrium growth conditions. Independent claims are included for methods for preparing (I), involving growing SiC single crystals in a growth reactor by a physical vapor transport (PVT) process, where either: (1) a water vapor density of at least 2 g/m3 is present in the reactor before the start of the growth process; or (2) the growth reactor and the growth support are purged with a gas forming a gaseous compound with S before the start of the actual growth process.