Ultrathin HfOxNy Gate Insulator Formation by Electron Cyclotron Resonance Ar/N2 Plasma Nitridation of HfO2 Thin Films

Shun-ichiro OHMI
Tomoki KUROSE
Masaki SATOH

Publication
IEICE TRANSACTIONS on Electronics   Vol.E89-C    No.5    pp.596-601
Publication Date: 2006/05/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e89-c.5.596
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Fundamental and Application of Advanced Semiconductor Devices)
Category: Si Devices and Processes
Keyword: 
electron cyclotron resonance,  sputtering,  plasma nitridation,  postdeposition annealing,  high-k,  HfOxNy,  

Full Text: PDF(844.3KB)>>
Buy this Article


Summary: 
HfOxNy thin films formed by the electron cyclotron resonance (ECR) Ar/N2 plasma nitridation of HfO2 films were investigated for high-k gate insulator applications. HfOxNy thin films formed by the ECR Ar/N2 plasma nitridation (60 s) of 1.5-nm-thick HfO2 films, which were deposited on chemically oxidized Si(100) substrates, were found to be effective for suppressing interfacial layer growth or crystallization during postdeposition annealing (PDA) in N2 ambient. After 900 PDA of for 5 min in N2 ambient, it was found that HfSiON film with a relatively high dielectric constant was formed on the HfOxNy/Si interface by Si diffusion. An equivalent oxide thickness (EOT) of 2.0 nm and a leakage current density of 1.010-3 A/cm2 (at VFB-1 V) were obtained. The effective mobility of the fabricated p-channel metal-insulator-semiconductor field-effect transistor (MISFET) with the HfOxNy gate insulator was 50 cm2/Vs, and the gate leakage current of the MISFET with the HfOxNy gate insulator was found to be well suppressed compared with the MISFET with the HfO2 gate insulator after 900 PDA because of the nitridation of HfO2.