Characterizations of NiSi 2 -Whisker Defects in n-Channel Metal–Oxide–Semiconductor Field-Effect Transistors with Channel on Si(100)

• Published in: Japanese Journal of Applied Physics 2010-12, Vol.49 (12R), p.126503
• Main Authors: Yamaguchi, Tadashi, Kashihara, Keiichiro, Kudo, Shuichi, Tsutsumi, Toshiaki, Okudaira, Tomonori, Maekawa, Kazuyoshi, Hirose, Yukinori, Asai, Koyu, Yoneda, Masahiro
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.49.126503

Electrical and physical characteristics of nickel disilicide (NiSi 2 )-whisker defects in n-channel metal–oxide–semiconductor field-effect transistors (nMOSFETs) on Si(100) have been investigated. NiSi 2 -whisker defects are easily generated in narrow-channel-width nMOSFETs with the channel on Si(100) and anomalously increase the leakage current between the drain and the source. A NiSi 2 whisker elongates toward the direction along the trench edge and pierces the channel region. These physical properties of NiSi 2 -whisker defects were revealed by detailed failure analyses. The influence of the recessed depth of trench-fill oxides on NiSi 2 -whisker defects was also investigated. Furthermore, it is found that trench-edge defects, such as Si(111) stacking faults, are generated in the channel before the Ni silicide formation. These trench-edge defects were not observed in the channel. We also propose a generation model for NiSi 2 -whisker defects. The nucleation of NiSi 2 precipitates might be generated at trench-edge defects, and Ni atoms diffuse toward the direction during the silicidation annealing. As a result, NiSi 2 -whisker defects are generated toward the direction at the trench edge.