Comparative study of phonon‐limited mobility of two‐dimensional electrons in strained and unstrained Si metal–oxide–semiconductor field‐effect transistors
Comparative study of phonon‐limited mobility of two‐dimensional electrons in strained and unstrained Si metal–oxide–semiconductor field‐effect transistors
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DOI：
10.1063/1.362953
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发表时间：
1996-08
影响因子：
3.2
通讯作者：
S. Takagi;J. Hoyt;J. Welser;J. Gibbons
中科院分区：
文献类型：
--
作者：
S. Takagi;J. Hoyt;J. Welser;J. Gibbons
通过包括二维量子化在内的理论计算，研究了在SiGe衬底上制备的应变Si金属氧化物半导体场效应晶体管(MOSFET)的声子限制迁移率，并与传统的(非应变)Si MOSFET的迁移率进行了比较。为了匹配无应变硅MOSFET的迁移率和应变硅MOSFET的迁移率增强，与传统模型相比，有必要增加二维气体中电子与谷间声子的耦合。与应变相关的迁移率增强归因于以下两个因素：应变引起的能带分裂抑制了谷间声子散射，以及由于与谷间声子的较强相互作用而表现出较低迁移率的四重谷的占有率减少。而由于四重谷占有率的降低而导致的平均电导率质量的降低，也是导致电导率降低的主要原因。
The phonon‐limited mobility of strained Si metal–oxide–semiconductor field‐effect transistors (MOSFETs) fabricated on a SiGe substrate is investigated through theoretical calculations including two‐dimensional quantization, and compared with the mobility of conventional (unstrained) Si MOSFETs. In order to match both the mobility of unstrained Si MOSFETs and the mobility enhancement in strained Si MOSFETs, it is necessary to increase the coupling of electrons in the two‐dimensional gas with intervalley phonons, compared to the values used in conventional models. The mobility enhancement associated with strain in Si is attributed to the following two factors: the suppression of intervalley phonon scattering due to the strain‐induced band splitting, and the decrease in the occupancy of the fourfold valleys which exhibit a lower mobility due to the stronger interaction with intervalley phonons. While the decrease in the averaged conductivity mass, caused by the decrease in the occupancy of the fourfold valle...