Publications Details
Temperature Dependence of Charge Distributions and Carrier Mobility in an Undoped Si/SiGe Heterostructure
Hsu, Nai-Wen; Hou, Wei-Chih; Chen, Yen-Yang; Wu, Yu-Jui; Kao, Hsiang-Shun; Harris, Charles T.; Lu, Tzu-Ming L.; Li, Jiun-Yun
Capacitance–voltage (C–V ) characteristics and carrier transport properties of 2-D electron gases (2DEGs) in an undoped Si/SiGe heterostructure at T = 4 – 35 K are presented here. In this work, two capacitance plateaus due to density saturation of the 2DEG in the buried Si quantum well (QW) are observed and explained by a model of surface tunneling. The peak mobility at 4 K is 4.1 × 105 cm2/V·s and enhanced by a factor of 1.97 at an even lower carrier density compared to the saturated carrier density, which is attributed to the effect of remote carrier screening. At T = 35 K, the mobility enhancement with a factor of 1.35 is still observed, which suggests the surface tunneling is still dominant.