Nonvolatile semiconductor device

Abstract

The invention provides a nonvolatile semiconductor device, or the like. According to the fabrication process of the present invention, silica glass containing boron or phosphorous is used as a material of high absorbency, which is treated in the vapor phase HF atmosphere and, therefore, selective etching of silica glass, only, of high absorbency becomes possible so that a void area can be formed beneath the fin of the floating gate. Accordingly, the absolute value of the parasitic capacitance between the floating gate and the substrate is decreased. In addition, the degree of the fluctuation of the parasitic capacitance due to the manufacturing process can be restricted to a low level. Accordingly, a nonvolatile semiconductor device of high performance can be gained without lowering the yield.

Dependencies are inferred from the claim text.