(Invited) Technology Options to Reduce Contact Resistance in Nanoscale III-V MOSFETs

III-V semiconductors have emerged as a leading candidate to replace Si as channel material in future low power logic applications. To realize the full performance benefits of III-V channels, it is crucial that external parasitic resistance (REXT) be minimized. Among the different components of REXT, contact resistance (RC) between metal and source/drain (S/D) junctions has become a critical area of focus to lower REXT. Historically, multi-layered Au-based metal contacts (e.g. Au/Ge/III-V) were used in III-V processing. However, the renewed interest in III-V semiconductors for CMOS has attracted an increasing interest by many to develop Au-free contacts to III-V with low RC. In addition, a “silicide-like” metal contact process for III-V was recently developed by reacting Ni with InGaAs to form Ni-InGaAs. This is significant as it is a self-aligned process and it offers the option of using a common S/D contact metal in a hetero-integrated device flow (e.g. Si/Ge/III-V). In this paper, we will review these technology options for RC reduction and present some of our recent results on contact/junction engineering to lower RC in III-V transistors.