Meltback etching and regrowth of GaAs/AlGaAs in liquid phase epitaxy for fabrication of microlens

Meltback etching was performed both on planar and selective areas. In the case of planar etching, we could see the effect of convection. Such a tendency was observed also for selective etching when the degree of undersaturation was large. By varying the mask opening area, composition of the melt, and etching time, a precise control of the etched shape was possible and a hemispherical shape was obtained. Large anisotropic meltback behavior was apparent when the melt contained no aluminium content. But as the added amount of aluminium was increased, the etched shape became circular. Regrowth characteristics showed gallium capturing phenomenon when the amount of supersaturated arsenic was large. By reducing the supersaturated arsenic content, a successful growth could be obtained.