Effects of Sulfur Passivation on Germanium MOS Capacitors With HfON Gate Dielectric

Author

Xie, Ruilong ; Zhu, Chunxiang

Author_Institution

Nat. Univ. of Singapore, Singapore

Volume

28

Issue

11

fYear

2007

Firstpage

976

Lastpage

979

Abstract

In this letter, we study the effects of sulfur (S) passivation, using aqueous ammonium sulfide ((NH₄)₂S), on germanium (Ge) MOS capacitors with sputtered HfON as gate dielectric and TaN as metal-gate electrode. Compared with control samples, the S passivation can effectively reduce both equivalent oxide thickness and interface-state density. X-ray-photoelectron-spectroscopy analysis shows that (NH₄)₂S treatment can reduce the Ge-O bonds on Ge surface. The thermal stability of the S passivation under different postmetal-annealing temperatures was also examined, and it was found that samples with (NH₄)₂S treatment exhibit stable Ge/high-fc interface upon 550-deg C postmetal-deposition annealing, whereas interface quality degrades for those samples without S passivation.

Keywords

MOS capacitors; X-ray photoelectron spectra; ammonium compounds; annealing; dielectric materials; elemental semiconductors; germanium; hafnium compounds; passivation; sulphur; tantalum compounds; thermal stability; (NH₄)₂S; Ge; Ge MOS capacitors; HfON; HfON gate dielectric; TaN metal-gate electrode; X-ray-photoelectron-spectroscopy; aqueous ammonium sulfide; equivalent oxide thickness; germanium MOS capacitors; interface-state density; postmetal-deposition annealing; sulfur passivation effects; thermal stability; Annealing; Dielectrics; Electrodes; Germanium; MOS capacitors; Passivation; Surface treatment; Temperature; Thermal stability; Thickness control; Germanium (Ge); MOS capacitor; sulfur (S) passivation;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2007.907415

Filename

4367577