A New Experimental Determination of Transport Parameters in High Performance Schottky-Barrier MOSFETs

• Main Authors: Cheng, Xhiz-Song, 鄭士嵩
• Other Authors: Chung, Steve S.
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/96242599112857809132

碩士 === 國立交通大學 === 電子研究所 === 99 === In recent years, SBMOS with metal-silicided source/drain has received much attention for its better Ion/Ioff ratio and the immunity to short channel effect but has shown a worse performance due to Schottky junction at the silicide and the channel. In order to alleviate the barrier height of S/D Schottky junction and to improve the performance, Dopant-Segregated SBMOS (DSS) is introduced, and a better enhancement on the carrier velocity has also been observed because of the strong velocity overshoot phenomenon. However, it has been not clear on the mechanism of the enhancement in overshoot velocity. Thus, the analysis of the transport efficiency is mandatory. The ballistic theory has been extended to explore the transport efficiency in quasiballistic regime. In this thesis, a new approach called Velocity Saturation Model (VSM), based on experimental measurements, is developed to study the ballistic efficiency, Bsat, and injection velocity (vinj) for DSS. We first introduce the basic properties of DSS including structure of device, manufacturing process, operating principle, and electrical characteristics. Then, we discuss and compare the ballistic efficiency extracted by the TDM(Temperature Dependent Method) and VSM respectively. For VSM, we obtain a reasonable relationship of performance, compared to TDM. Moreover, the experimental results showed that the value of Bsat is improved with reducing the channel length, resulting in a better enhancement of the performance, but not agreed with the results of TDM. Additionally, the strained-Si device with CESL is further discussed. It demonstrates that the vinj dominates the improvement of the performance since the strained channel induces a low effective mass. iv Finally, it was concluded that: (1) with the shrinkage of channel length, the DSS exhibits high performance; (2) the determination of Bsat by VSM is applied to DSS, which offers more reliable results than TDM; (3) the enhancement in DSS increases with decreasing channel length because of the increase of the Bsat; (4) the improvement of performance in strained-Si device with CESL is induced by high vinj. Consequently, the VSM provides us more accurate and reliable results than the TDM ones.