Ultra-thin semiconductor membranes

Abstract

This invention relates to ultra-thin semiconductor films which can be in the submicron range formed from semiconductor materials such as silicon, germanium and gallium arsenide. The films are formed by creating a thin slightly damaged surface on the polished reverse side of a film (e.g., a wafer) of the semiconductor by low dose ion implantation and then etching the semiconductor material on the front side of the film to remove the semiconductor material down to the ion implanted damaged layer. While the implanted ions can be chosen from functionally desirable ions which upon annealing remain in the film to alter the original electrical characteristics, the implanted ions can also be chosen so that upon annealing, the resultant ultra-thin semiconductor film has the same electrical characteristics as the original semiconductor material. The ion implantation changes the etching characteristics of the ion implanted layer. Thus, when the partially damaged semiconductor material is exposed to an etchant the etching rate in the damaged region is decreased by a factor of several thousand as compared to the undamaged semiconductor material.