Manufacture of nonvolatile semiconductor memory device

Abstract

Abstract PURPOSE:To enable the titled device of good memory holding characteristic to be produced safely and easily at room temperature by a method wherein the surface level is reduced by hydrogen ion implantation without using high-temperature hydrogen annealing for reducing the surface level of the interface between an Si substrate and an SiO2 film. CONSTITUTION:A field SiO2 film 2 is formed by surrounding the active region on selective oxidation of the Si substrate 1, and an extremely thin SiO2 film 3 is formed on the surface of the active region; thereafter, an Si3N4 film 4 is deposited on the SiO2 film 2 and the SiO2 film 3 by CVD. Further, a polycrystalline Si layer 5 is formed by deposition likewise by CVD and changed into N type by phosphorus deposition. Successively, unnecessitated photo resist is removed by leaving a polycrystalline Si gate electrode 5a, a gate Si3N4 film 4a, and a gate SiO2 film 3a by plasma etching through the photo engraving technique, using a mask of a photo resist pattern for gate electrode formation; thereafter, phosphrous ions are implanted to form an n<+> type source region 6 and an n<+> type drain region 7, and then activated by annealing. Then, the surface level in the interface is reduced by hydrogen ion implantation.

Inventors

• 👤 Kazuaki Miyata
• 👤 和明 宮田

Bibliographic Details