Effects of interfacial sulfidization and thermal annealing on the electrical properties of an atomic-layer-deposited Al2 O3 gate dielectric on GaAs substrate

Chao Ching Cheng*, Chao-Hsin Chien, Guang Li Luo, Chun Hui Yang, Ching Chih Chang, Chun Yen Chang, Chi Chung Kei, Chien Nan Hsiao, Tsong Pyng Perng

*Corresponding author for this work

研究成果: Article同行評審

15 引文 斯高帕斯(Scopus)

摘要

In this study we investigated the interfacial chemistry occurring between an atomic-layer-deposited Al2 O3 high- k film and a GaAs substrate and the impact of sulfidization and thermal annealing on the properties of the resultant capacitor. We observed that sulfide passivation of the Al2 O3 GaAs structure improved the effect of Fermi level pinning on the electrical characteristics, thereby providing a higher oxide capacitance, smaller frequency dispersion, and reduced surface states, as well as decreased interfacial charge trapping and gate leakage currents. Photoemission analysis indicated that the (N H4)2 S -treated GaAs improved the quality of the as-deposited Al2 O3 thin film and preserved the stoichiometry of the dielectric during subsequent high-temperature annealing. This behavior was closely correlated to the diminution of GaAs native oxides and elemental arsenic defects and their unwanted diffusion. In addition, thermal processing under an O2 atmosphere, relative to that under N2, decreased the thickness of the Al2 O3 gate dielectric and relieved the gate leakage degradation induced by metallic arsenic; as a result, superior dielectric reliability was attained. We discuss the underlying thermochemical reactions that account for these experimental observations.

原文English
文章編號074102
期刊Journal of Applied Physics
103
發行號7
DOIs
出版狀態Published - 21 四月 2008

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