This letter reports an anomalous subthreshold characteristic of MOSFET for the first time. It is observed that the subthreshold characteristic does not change as the channel length decreases. The cause of channel length independent subthreshold characteristics is identified as the localized pileup of channel dopants near the source and drain ends of the channel. The low surface potential of this pileup region limits the subthreshold current of MOSFET. As a result, the ratio of on-current to off-current for this MOSFET increases as the channel length is reduced, which is an important parameter for low-voltage operation. It is found that a MOSFET with channel length independent subthreshold characteristic is more suitable for low-voltage operation.
Bibliographical noteFunding Information:
Manuscript received April 24, 1997; revised November 6, 1997. This work was supported by the Electronics and Telecommunications Research Institute, Korea. H. S. Shin is with the Department of Electronics Engineering, Ewha Woman’s University, Seodaemoon-Gu, Seoul, Korea. C. Lee is with the Department of Electronic Engineering, Soong Sil University, Dong Jak-Gu, Seoul, Korea. S. W. Hwang is with the Department of Electronics Engineering, Korea University, Seoul, Korea. B. G. Park, Y. J. Park, and H. S. Min are with the Department of Electronics Engineering, Seoul National University, Shinlim-Dong, Gwanak-Gu, Seoul, Korea. Publisher Item Identifier S 0741-3106(98)01965-X.