A two-step removing GaAs substrate technique by using HNO3 solution is reported. In the authors' experiments, as compared with other ratios, the etch rate of HNO3:H2O2:H2O=1:6:1 is faster. In addition, the etched surface by nitric acid solution has about 0.15 mu m of surface smoothness. The high selectivity of HNO3:H2O2:H2O=1:4:1 for GaAs/GaInP is demonstrated with smooth morphology whose roughness is about 4.57 nm. The advantages of this technique are easy, repeatable, and no contamination. It is a very useful process in the light-emitting diode fabrication. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3431082]