POROUS GAAS FORMED BY A 2-STEP ANODIZATION PROCESS

In this letter, we proposed a method in which a n-type GsAs wafer was first anodized in HF for a short time to form a high density of etch p its on its surface and then anodized in KOH solution to form a high de nsity of pores with uniform distribution in it. Scanning electron micr oscopy revealed feature sizes of the porous structure in the nanometer range. The porous GaAs has been investigated using double crystal X-r ay diffraction technique. Crystal quality and crystallographic orienta tion of the porous layer were similar to those of the substrate. The l attice constant of porous layer is slightly larger than that of the su bstrate in the growth direction.