Method of manufacturing a thin dielectric layer using a heat treatment and a semiconductor device formed using the method

Abstract

In a method for forming a semiconductor device and a semiconductor device formed in accordance with the method, a thin dielectric layer is provided between a lower conductive layer and an upper conductive layer. In one embodiment, the thin dielectric layer comprises an inter-gate dielectric layer, the lower conductive layer comprises a floating gate and the upper dielectric layer comprises a control gate of a transistor, for example, a non-volatile memory cell transistor. The thin dielectric layer is formed using a heat treating process that results in reduction of surface roughness of the underlying floating gate, and results in a thin silicon oxy-nitride layer being formed on the floating gate. In this manner, the thin dielectric layer provides for increased capacitive coupling between the lower floating gate and the upper control gate. This also leads to a lowered programming voltage, erasing voltage and read voltage for the transistor, while maintaining the threshold voltage in a desired range. In addition, the size of the transistor and resulting storage cell can be minimized and the need for a high-voltage region in the circuit is mitigated, since, assuming a lowered programming voltage, pumping circuitry is not required.