A Self-Aligned Ni-InGaAs Contact Technology for InGaAs Channel n-MOSFETs

Abstract

A salicide-like self-aligned Ni-InGaAs contact technology suitable for InGaAs metal-oxide-semiconductor field-effect transistors has been developed. It has been confirmed that Ni film sputtered onto single crystalline InGaAs substrate is uniformly converted into Ni-InGaAs by low temperature (250–400°C) rapid thermal annealing. A comprehensive study of Ni-InGaAs contacts was performed by employing characterization of High Resolution Transmission Electron Microscopy, Energy-dispersive X-ray spectroscopy, X-Ray Diffraction and Secondary Ion Mass Spectroscopy. The electrical properties of the contacts were also characterized. Sheet resistance mapping of Ni-InGaAs thin film by microscopic 4-point probe shows a uniform sheet resistance of 21.3 Ω/□ and low resistivity of ∼96 μΩ·cm. Transfer Length Method test structure shows Ni-InGaAs has a contact resistance of 1.27 Ω·mm on n+ InGaAs doped by Si+ implant. This self-aligned Ni-InGaAs contact technology was then used in the experimental fabrication of InGaAs channel n-MOSFETs. Devices with self-aligned metallic Ni-InGaAs S/D as well as Si-doped S/D with Ni-InGaAs contacts were realized and show good electrical characteristics with on-state/off-state drain current ratio of 103∼105.