Ge 组分对应变 Si1-x Gex 沟道 P-MOSFET 电学特性影响

Effects of Ge fraction on electrical characteristics of strained Si_(1-x)Ge_x channel p-MOSFET

利用二维数值模拟方法,研究了不同Ge组分应变Si1-xGex沟道p-MOSFET的电容-电压特性以及阈值电压的变化情况.计算结果表明:提高应变Si1-xGex沟道层中的Ge组分,器件亚阈值电流明显增大;栅电容在器件进入反型状态时产生显著变化;阈值电压的改变量与Ge组分基本成线性关系.通过改变Si1-xGex沟道的长度,并结合相关物理模型,在低电场情况下,沟道中的空穴迁移率与总电阻对沟道长度的微分成反比关系.

The capacitance-voltage characteristics and the variations of threshold vohage of strained Si1-x Gex channel p-MOSFET with Ge fraction are investigated via two-dimansional numerical simulation. The results indicate that with the increase of Ge fraction, the subthreshold current increases remarkably, and that the gate capacitance changes significantly when the device is in inversion, moreover, the Ge fraction dependence of the variation of threshold voltage is linear. Combining the change of the Si1-x Gex channel length with the relevant physical model, the mobility of holes in channel is demonstrated to be inversely proportional to the derivative of the total resistances with respect to the channel length in a weak applied field.