Programme

P.18 -- Poster, VCTP-44

Date: Tuesday, 30 July 2019

Time: 08:30 - 10:00

Is the Nonlocal Band-to-Band Tunneling Model Proper for Caculating the Tunneling Current in Tunnel Devices?

Nguyen Dang Chien (1), Chun-Hsing Shih (2)

(1) Dalat University; (2) National Chi Nan university

Based on the assumption of a nonlocal electric field applied in the Kane formalism, the nonlocal band-to-band tunneling (BTBT) model has been successfully applied for a long time to analytically and numerically predict the BTBT current in tunnel devices such as Esaki diodes and tunnel field-effect transistors (TFETs). Although the mixed BTBT model has recently been suggested, the nonlocal BTBT model is still widely used, particularly integrated in the well-known TCAD simulators, for example, Synopsys Sentaurus Devices and Silvaco ATLAS. In this study, we tried to answer the question whether the nonlocal BTBT model is proper to calculate the tunneling current in tunnel devices. To do that, we applied the symmetric principle that if two tunnel devices are completely symmetric, their current-voltage characteristics also have to be strictly symmetric. By using two couples of ideally symmetric devices, including both two and three terminal devices, it is shown that the current-voltage characteristics of each symmetric couple calculated by the mixed model are always symmetric, whereas the symmetric property of those calculated by the nonlocal approach depends on the chosen integrating path. With the fact that the integrating path in the nonlocal model is arbitrarily assumed without definitely physical reasons, it infers that the nonlocal BTBT model is not proper, but the mixed BTBT one is, for calculating the tunneling current in tunnel devices.

Presenter: Nguyen Dang Chien