Design of GeSn-Based Heterojunction-Enhanced N-Channel Tunneling FET With Improved Subthreshold Swing and ON-State Current

Author

Mingshan Liu ; Yan Liu ; Hongjuan Wang ; Qingfang Zhang ; Chunfu Zhang ; Shengdong Hu ; Yue Hao ; Genquan Han

Author_Institution

Key Lab. of Optoelectron. Technol. & Syst., Chongqing Univ., Chongqing, China

Volume

Issue

fYear

2015

fDate

Apr-15

Firstpage

1262

Lastpage

1268

Abstract

We design a heterojunction-enhanced n-channel tunneling FET (HE-NTFET) employing a Ge_1−xSn_x/Ge_1−ySn_y ( $x>y$ ) heterojunction located in the channel region with a distance of $L_{\\rm T-H}$ from the source-channel tunneling junction. We investigate the impact of $L_{\\rm T-H}$ on the performance of HE-NTFETs by simulation. HE-NTFETs achieve a positive shift of $V_{\\rm ONSET}$ , a steeper subthreshold swing (SS), and an enhanced $I_{math\\rm{{\\scriptscriptstyle ON}}}$ compared with homo-NTFETs, which is attributed to the modulating effect of heterojunction on band-to-band tunneling (BTBT). At a supply voltage of 0.3 V, 304% $I_{math\\rm{{\\scriptscriptstyle ON}}}$ enhancement is demonstrated in the Ge_0.92Sn_0.08/Ge_0.94Sn_0.06 HE-NTFET with a 4 nm $L_{\\rm T-H}$ over Ge_0.92Sn_0.08 homo-NTFET due to the steeper average SS. The impact of Sn composition on the performance of HE-NTFETs is also studied. As we increase the difference in Sn composition $x-y$ across the heterojunction, $I_{math\\rm{{\\scriptscriptstyle ON}}}$ and SS of HE-NTFETs are improved due to the increase in band offsets at the Ge_{1−xSn_x/Ge_1−ySn_y interface, which leads to the enhanced modulating effect of heterojunction on BTBT.}

Keywords

field effect transistors; germanium compounds; semiconductor heterojunctions; tunnel transistors; Ge_0.92Sn_0.08; Ge_0.94Sn_0.06; HE-NTFET; band-to-band tunneling; heterojunction-enhanced N-channel tunneling FET; improved subthreshold swing; on-state current; size 4 nm; source-channel tunneling junction; voltage 0.3 V; Educational institutions; Heterojunctions; Performance evaluation; Photonic band gap; Semiconductor process modeling; Tin; Tunneling; Band-to-band tunneling (BTBT); Germanium-Tin (GeSn); heterostructure; steep subthreshold swing (SS); tunneling FET (TFET); tunneling FET (TFET).;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/TED.2015.2403571

Filename

7050321

Link To Document

https://search.isc.ac/dl/search/defaultta.aspx?DTC=49&DC=81478