Extraction of large valence-band energy offsets and comparison to theoretical values for strained-Si/strained-Ge type-II heterostructures on relaxed SiGe substrates

被引:37
作者
Teherani, James T. [1 ]
Chern, Winston [1 ]
Antoniadis, Dimitri A. [1 ]
Hoyt, Judy L. [1 ]
Ruiz, Liliana [2 ]
Poweleit, Christian D. [3 ]
Menendez, Jose [3 ]
机构
[1] MIT, Cambridge, MA 02139 USA
[2] Univ Texas Brownsville, Brownsville, TX 78520 USA
[3] Arizona State Univ, Tempe, AZ 85287 USA
基金
美国国家科学基金会;
关键词
DEFORMATION POTENTIALS; QUANTUM-WELLS; MOBILITY; GAP; STRESS; HETEROJUNCTIONS; LUMINESCENCE; SPECTROSCOPY; PARAMETERS; INTERFACE;
D O I
10.1103/PhysRevB.85.205308
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Metal-oxide-semiconductor capacitors were fabricated on type-II staggered gap strained-Si/strained-Ge heterostructures epitaxially grown on relaxed SiGe substrates of various Ge fractions. Quasistatic quantum-mechanical capacitance-voltage (CV) simulations were fit to experimental CV measurements to extract the band alignment of the strained layers. The valence-band offset of the strained-Si/strained-Ge heterostructure was found to be 770, 760, and 670 meV for 35, 42, and 52% Ge in the relaxed SiGe substrate, respectively. These values are approximately 100 meV larger than the usually recommended band offsets for modeling Si/Ge structures. It is shown that the larger valence-band offsets found here are consistent with an 800-meV average valence-band offset between Si and Ge, which also explains the type-II band alignment observed in strained-Si1-xGex on unstrained-Si heterostructures.
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页数:10
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