Relaxed germanium-tin P-channel tunneling field-effect transistors fabricated on Si: impacts of Sn composition and uniaxial tensile strain

Abstract

In this work, relaxed GeSn p-channel tunneling field-effect transistors (pTFETs) with various Sn compositions are fabricated on Si. Enhancement of on-state current ION with the increase of Sn composition is observed in transistors, due to the reduction of direct bandgap EG. Ge0.93Sn0.07 and Ge0.95Sn0.05 pTFETs achieve 110% and 75% enhancement in ION, respectively, compared to Ge0.97Sn0.03 devices, at VGS - VTH = VDS = - 1.0 V. For the first time, ION enhancement in GeSn pTFET utilizing uniaxial tensile strain is reported. By applying 0.14% uniaxial tensile strain along [110] channel direction, Ge0.95Sn0.05 pTFETs achieve 12% ION improvement, over unstrained control devices at VGS - VTH = VDS = - 1.0 V. Theoretical study demonstrates that uniaxial tensile strain leads to the reduction of direct EG and affects the reduced tunneling mass, which bring the GBTBT rising, benefiting the tunneling current enhancement in GeSn TFETs.

Non-Silicon microelectronics: Germanium and Germanium-Tin field-effect transistors

“…GeSn TFET器件 [12] . 研究人员利用低温固源分子束外 图 17 生长在Si(100), (110)和(111)的Ge:B样品的SIMS测试图 [59] Figure 17 SIMS profiles of Boron for Ge:B films grown on Si(100), ( 110) and (111) substrates [59].…”

“…中国科学院半导体研究所在 国内率先开展了IV族材料外延生长的研究工作, 研制 出了具有国内领先、国际先进水平的Ge和GeSn材料, 包括Si衬底上Ge和GeSn、Ge衬底上应变GeSn、SOI 上压应变Ge及GeOI, 这些材料方面的研究为FET器件 的研制奠定了夯实的基础. 西安电子科技大学在GeSn TFET器件方面也做了深入的研究 [12,58,63,69] .…”

“…基于量子隧穿的 晶体管概念出现于19世纪80年代 [6] , 1995年, Reddick等 人 [7] 报道了Si表面隧穿晶体管. 目前, 报道的TFET材 料主要包括Si, Ge, GeSn与InAs [8][9][10][11][12][13] 等. 下面重点介绍 表 1 高迁移率沟道材料参数 [1] Table 1 Parameters of high mobility channel materials [ 1 Ge沟道CMOS器件…”

“…网络版彩图)Si衬底上的弛豫和单轴张应变Ge0.95Sn0.05 TFET的转移特性曲线(a)和输出特性曲线(b), 0.14%的单轴张 应变沿[110]沟道方向, 沿沟道方向施加单轴应变可以提高隧穿电流[12] …”

Theoretical calculation of performance enhancement in lattice-matched SiGeSn/GeSn p-channel tunneling field-effect transistor with type-II staggered tunneling junction

“…GeSn has attracted extensive research interest as a pchannel TFET material because of its direct BTBT and easy integration on a Si platform. 12,[14][15][16][17][18][19][20] GeSn alloys can exhibit a direct bandgap by adjusting the Sn composition and strain. Therefore, GeSn TFETs can achieve a high direct BTBT rate, which contributes to the improvement of I ON compared with the devices based on other group IV alloys.…”