Method of forming an nrom embedded with mixed-signal circuits

Abstract

A method of forming an NROM comprising mixed-signal circuits is provided. The method starts by providing a semiconductor substrate having a memory area and a periphery area. The periphery area has a plurality of active areas isolated by an isolation layer. A bottom electrode of a capacitor is formed atop the isolation layer in the periphery area. An ONO(oxide-nitride-oxide) process is performed. A photolithography, an anisotropic etching, and an ion implantation process are performed in order to etch the ONO dielectric layer in a bit line region not protected by the first photolithography process, and to form a plurality of buried bit lines. A photolithography and an ion implantation process are performed in order to form at least one ion well. The surface of the active area in the periphery area is wet etched. An oxidation process is performed in order to simultaneously form at least one gate oxide layer with a specific thickness in the active area, and to form a thermal oxide layer atop each of the buried bit lines in the memory area. Each of the gates, the top electrode of the capacitor and the resistor are formed in the periphery area, and a word line is formed in the memory area.