Temperature Dependence of Charge Distributions and Carrier Mobility in an Undoped Si/SiGe Heterostructure

• Published in: IEEE transactions on electron devices Vol. 69; no. 2; pp. 482 - 486
• Main Authors: Hsu, Nai-Wen, Hou, Wei-Chih, Chen, Yen-Yang, Wu, Yu-Jui, Kao, Hsiang-Shun, Harris, Charles Thomas, Lu, Tzu-Ming, Li, Jiun-Yun
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.02.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: <italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">C-V characteristics; Capacitance; Carrier density; Carrier mobility; Carrier transport; Charge carrier density; Current carriers; C–V characteristics; ENGINEERING; Heterostructures; Logic gates; Quantum wells; Silicon; Silicon germanides; surface tunneling; Temperature; Temperature dependence; Transport properties; Tunneling; undoped Si/SiGe heterostructure; Voltage measurement
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2021.3138363

Capacitance-voltage (<inline-formula> <tex-math notation="LaTeX">{C} </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">{V} </tex-math></inline-formula>) characteristics and carrier transport properties of 2-D electron gases (2DEGs) in an undoped Si/SiGe heterostructure at <inline-formula> <tex-math notation="LaTeX">{T}= {4} - {35} </tex-math></inline-formula> K are presented. 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 <inline-formula> <tex-math notation="LaTeX">\times 10^{{5}} </tex-math></inline-formula> cm 2 /<inline-formula> <tex-math notation="LaTeX">\text{V}\cdot \text{s} </tex-math></inline-formula> 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 <inline-formula> <tex-math notation="LaTeX">{T}\,\,=35 </tex-math></inline-formula> K, the mobility enhancement with a factor of 1.35 is still observed, which suggests the surface tunneling is still dominant.