AIP Advances 5, 117112 (2015)

J. Q. Liu¹, C. Wang¹, T. Zhu¹, W. J. Wu¹, J. Fan^1,2 and L. C. Tu^1,2,a)

¹ MOE Key Laboratory of Fundamental Physical Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China

² Institute of Geophysics, Huazhong University of Science and Technology, Wuhan 430074, People’s Republic of China

^a) Corresponding author: tlc@hust.edu.cn

This paper investigates low temperature ohmic contact formation of Au/Sb to n-type Si substrates through AuSb/NiCr/Au metal stacks. Liquid epitaxy growth is utilized to incorporate Sb dopants into Si substrate in AuSi melt. The best specific contact resistivity achieved is 0.003 Ω ⋅ cm² at 425 ^oC. Scanning electron microscopy (SEM) reveals inverted pyramidal crater regions at the metal/semiconductor interface, indicating that AuSi alloying efficiently occurs at such sites. Secondary ion mass spectroscopy (SIMS) shows that Sb atoms are successfully incorporated into Si as doping impurities during the anneal process, and the Sb doping concentration at the contact interface is found to be higher than the solid solubility limit in a Si crystal. This ohmic contacts formation method is suitable for semiconductor fabrication processes with limited thermal budget, such as post CMOS integration of MEMS.

http://scitation.aip.org/content/aip/journal/adva/5/11/10.1063/1.4935442

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