Influence of hetero-gate dielectrics on short-channel effects in scaled tunnel field-effect transistors

• Published in: Current applied physics Vol. 20; no. 12; pp. 1342 - 1350
• Main Authors: Chien, Nguyen Dang, Vinh, Luu The, Hong Tham, Huynh Thi, Shih, Chun-Hsing
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2020; 한국물리학회
• Subjects: Band-to-band tunneling; Double-gate; Hetero-gate dielectric; Short-channel effect; Tunnel field-effect transistor; 물리학; Short-channel effect; Double-gate; Band-to-band tunneling; Hetero-gate dielectric; Tunnel field-effect transistor
• ISSN: 1567-1739; 1878-1675
• DOI: 10.1016/j.cap.2020.09.004

In this study, we examined the influence of using hetero-gate dielectrics (HGDs) on the short-channel effects (SCEs) in scaled tunnel field-effect transistors (TFETs). For bulk TFETs, the short-channel performance is not influenced by the HGD engineering because the SCEs are caused by the tunneling at the region with negligible gate control. However, the use of the HGD increases the SCEs in double-gate TFETs because the HGD reduces the gate control on the channel. When the HGD optimized in term of on-current is used, the channel of HGD-TFETs is about 10-nm longer than that of uniform-gate dielectric TFETs to obtain similar SCEs. The SCEs in HGD-TFETs can be improved by locating the drain-side heterojunction toward the drain and/or increasing the ratio of low- and high-k equivalent oxide thicknesses. Due to the trend of scaling transistors, an appropriate design of HGD to minimize the SCEs in scaled HGD-TFETs is also crucial. The short-channel performance of bulk TFETs is not influenced by the HGD engineering, but the use of HGDs increases SCEs in double-gate TFETs. The SCEs in HGD double-gate TFETs can be improved by locating the drain-side heterojunction toward the drain and/or increasing the low/high-k EOT ratio. [Display omitted] •The use of hetero-gate dielectrics (HGDs) significantly degrades the short-channel effects (SCEs) in double-gate TFETs.•The minimum scaled length of HGD TFETs is approximately 10-nm longer than that of the non-HGD counterparts.•The SCEs in HGD-TFETs are improved by locating the drain-side heterojunction toward the drain or increasing the EOT ratio.