It was confirmed that the optimum volume ratio of 50% citric acid solution to 30% H2O2 is 1.5 : 1.The LT GaAs cap layer of GaAs MESFET was etched off with the 50% citric acid/H2O2 solution, and the AlAs spacer layer with hydrochloric acid.

• 分析了选择腐蚀机理；确定了腐蚀工艺中50%25柠檬酸:H_2O_2=1.；5:1的最佳腐蚀液配比方案。