HEAT TREATMENT METHOD OF GAAS BOARD AND GAAS BOARD

摘要

PURPOSE: To obtain a GaAs board wherein frequency characteristic in low frequencies is flat when an FET is prepared by GaAs single crystal by providing a board with a mirror surface wherein a Ga rich layer wherein As atomic ratio As/(Ga+As) is within a specified range is formed on the surface. CONSTITUTION: A Ga rich layer wherein As/(Ga+As) is 0.5000 to 0.5002 is formed on a surface and mirror polishing is performed for it. It is desirable that the thickness of a Ga rich layer is 0.1 to 20μm and a part wherein atomic ratio of As/(Ga+As) is larger than 0.5002 is contained in a part excepting a surface. Heat treatment of a GaAs board is carried out by annealing a GaAs board under non-As atmosphere at 300 to 700 deg.C for 1 second to 10 hours. For example, the surface of a GaAs board is removed by a thickness of 0 to 100μm by etching or polishing, or a combination thereof and a mirror surface is formed. Or, heat treatment is carried out after a mirror surface is formed.