Evidence of hole direct tunneling through ultrathin gate oxide using P/sup +/ poly-SiGe gate

Author

Lee, Wen-Chin ; King, Tsu-Jae ; Hu, Chenming

Author_Institution

Dept. of Electr. Eng. & Comput. Sci., California Univ., Berkeley, CA, USA

Volume

20

Issue

6

fYear

1999

fDate

6/1/1999 12:00:00 AM

Firstpage

268

Lastpage

270

Abstract

P/sup +/ poly-Si and poly-Si/sub 0.75/Ge/sub 0.25/-gated PMOS transistors with ultrathin gate oxides of 25 and 29 /spl Aring/ were used for this study. The difference in the gate work function was used to determine the mechanisms of gate tunneling current in such thin gate oxides, Under negative gate bias (inversion bias), it was found that the source/drain terminal serves as a source of holes for small V/sub g/ value, and as gate bias increases (more negative), it becomes a hole sink. These observations can be interpreted in terms of two competing mechanisms. For the first time, hole direct tunneling is reported, Hole direct tunneling is the dominant mechanism for -2 V\n\n\t\t

Keywords

Ge-Si alloys; MOSFET; insulating thin films; semiconductor materials; tunnelling; work function; 25 angstrom; 29 angstrom; PMOS transistors; SiGe; electron direct tunneling; electron-hole pair generation; gate bias; gate tunneling current; gate work function; hole direct tunneling; hole sink; inversion bias; negative gate bias; source/drain terminal; ultrathin gate oxide; ultrathin gate oxides; Annealing; CMOS technology; Charge carrier processes; Current supplies; Electrons; Gate leakage; MOS devices; MOSFETs; Tunneling; Voltage;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/55.767094

Filename

767094