Si-doped gaas single crystal ingot and process for producing the same, and si-doped gaas single crystal wafer produced from si-doped gaas single crystal ingot

Abstract

This invention provides an Si doped GaAs single crystal ingot, which has a low crystallinity value as measured in terms of etch pit density (EPD) per unit area and has good crystallinity, and a process for producing the same. An Si-doped GaAs single crystal wafer produced in a latter half part in the growth of the Si doped GaAs single crystal ingot is also provided. A GaAs compound material is synthesized in a separate synthesizing oven (a crucible). An Si dopant is inserted into the compound material to prepare a GaAs compound material with the Si dopant included therein. The position of insertion of the Si dopant is one where, when the GaAs compound material is melted, the temperature is below the average temperature. After a seed crystal is inserted into a crucible for an apparatus for single crystal growth, the GaAs compound material with the Si dopant included therein and a liquid sealing compound are introduced into the crucible. The crucible is set in the apparatus for single crystal growth, where the mixture is heat melted and, while stirring the liquid sealing compound, the melt is solidified by a vertical temperature gradient method and the crystal is grown to prepare an Si doped GaAs single crystal ingot. In this case, an Si doped GaAs single crystal wafer is also produced in the latter half part of the growth of the ingot.