METHOD FOR OBSERVING SHAPE OF GROWN SOLID-LIQUID BOUNDARY FACE OF GAAS CRYSTAL

摘要

PURPOSE:To improve the optimum conditions of crystal growth and tendency to a lower dislocation density by etching an Si-doped GaAs crystal by a sulfuric acid etchant under photoirradiation then observing the shape of the soil-liquid boundary face. CONSTITUTION:After the sulfuric acid etchant (e.g.: H2SO4:H2O2:H2O=15:1:1) 12 is put into a glass vessel 14 under atm. temp., an Si-doped GaAs Miller wafer 11 is immersed therein. An optical fiber 15 which is provided at one end with a halogen light 13 for irradiation is disposed above the etchant 12. The fiber 15 is then irradiated with the light 13 and while the influence of heat generation is prevented, the surface of the wafer 11 is irradiated for 20-40min at 19,000-23,000 lux via the etchant 12, by which the surface is etched. Stripes of 50-200mum intervals which are the solid-liquid boundary face shape are formed on the surface of the wafer 11. The stripes are observed by a microscope, etc.