| 摘要 |
PURPOSE:To obtain a single crystal with few defects by causing etch pit density to be provided with a value over a specific value and no cell construction of etch pit on the whole surface of a substrate or causing the diameter of the cell construction to be provided with a value below a specified value even if etch pit density has the cell construction of pit etch. CONSTITUTION:A substrate having etch pit density of 50,000cm<-2> or more and no cell construction or having a cell construction with its radius of 50mum or less is employed as an FET substrate. A substrate of a compound semiconductor single crystal (GaAs, InP) having high etch pit density is manufactured in accordance with a condition in crystal growth or by processing after wafering it. For example, in using the former method, a substrate is pulled with high speed by use of the LEC method as it is, keeping density of impurities of materials for pulling up crystals below 10<15>cm<-2>. On the other hand, in using the latter method, ion having a large radius of an atom such as an argon ion is injected into a wafer to form defects positively on the wafer surface. |
