Comparison of Ohmic contact resistances of n- and p-type Ge source/drain and their impact on transport characteristics of Ge metal oxide semiconductor field effect transistors

作者：Oh Jungwoo^*; Huang Jeff; Chen Yen Ting; Ok Injo; Jeon Kanghoon; Lee Se Hoon; Sassman Barry; Loh Wei Yip; Lee Hi Deok; Ko Dea Hong; Majhi Prashant; Kirsch Paul; Jammy Raj

来源：Thin Solid Films, 2011, 520(1): 442-444.

DOI：10.1016/j.tsf.2011.06.025

• Ge MOSFETs
• Ohmic contact
• CMOS
• High mobility channel transistors

We report the results of a systematic study to understand low drive current of Ge-nMOSFET (metal-oxide-semiconductor field-effect transistor). The poor electron transport property is primarily attributed to the low dopant activation efficiency and high contact resistance. Results are supported by analyzing source/drain Ohmic metal contacts to n-type Ge using the transmission line method. Ni contacts to Ge nMOSFETs exhibit specific contact resistances of 10(-3)-10(-5) Omega cm(2), which is significantly higher than the 10(-7)-10(-8) Omega cm(2) of Ni contacts to Ge pMOSFETs. The high resistance of Ni Ohmic contacts to n-type Ge is attributed mainly to insufficient dopant activation in Ge (or high sheet resistance) and a high tunneling barrier. Results obtained in this work identify one of the root causes of the lower than expected Ge nMOSFET transport issue, advancing high mobility Ge channel technology.

• 出版日期2011-10-31