CHARACTERIZATION OF POLYSILICON OXIDES THERMALLY GROWN AND DEPOSITED ON THE POLISHED POLYSILICON FILMS

This work examines the characteristics of polyoxides thermally grown a nd deposited an polished polysilicon films. A well-controlled chemical mechanical polishing (CMP) process is also presented to achieve a pla nar surface morphology Tot polysilicon films. The thermally-grown and deposited polyoxides on the polished polysilicon films exhibit a lower leakage current, higher dielectric breakdown field, higher electron b arrier height, lower electron trapping, rate, lower density of trapped charges, and markedly higher charge to breakdown (Q(bd)) than the con ventional polyoxide. In particular, the deposited polyoxide on the pol ished polysilicon film has the highest dielectric breakdown field, low est electron trapping rate, and highest charge to breakdown due to the planar polyoxide/polysilicon interface. In addition, experimental res ults indicate that the trapped charges of the polished samples are loc ated in the polyoxides' upper portion, which differs from conventional polyoxides. Undoubtedly, the deposited polyoxide on the polished poly silicon film considered herein is the most promising candidate to yiel d optimum characteristics of polyoxide.