Self-aligned metal S/D GaSb p-MOSFETs using Ni-GaSb alloys

GaSb has stirred a significant interest over the recent years, due to its high bulk electron/hole mobility and optoelectronic properties [1]. Particularly, the high hole mobility makes GaSb one of the III-V materials promising for p-MOSFETs and fully-integrated CMOS applications. However, the device technologies for GaSb MOSFETs have not been fully developed yet. In this work, we address a novel formation technology of source and drain (S/D) for GaSb p-MOSFETs. One of the problems of the S/D formation in GaSb (and generally III-V) is the low dopant solubility and the necessity of high temperature annealing for dopant activation. However, thermal stability of the GaSb/oxide interfaces is low and, therefore, a S/D formation process with low thermal budget is strongly required [2]. Also, for deeply-scaled MOSFET fabrication, self-aligned S/D formation is mandatory. For these reasons, we introduce a salicide-like self-aligned metal S/D process by using Ni into GaSb. In this study, we present the results of the characterization of Ni-GaSb alloys formed by direct reaction between Ni and GaSb, which are suitable for S/D in GaSb p-MOSFETs. Finally, we demonstrate, for the first time, a GaSb p-MOSFET with self-aligned Ni-GaSb alloy S/D, which allows us to fabricate MOSFETs at temperature as low as 250°C.