Self-aligned-TiSi2 bottom contact with APM cleaning and post-annealing for sputtered-MoS2 film

Abstract

Electrical contact characteristics between self-aligned titanium silicide (TiSi2) and sputtered-molybdenum disulfide (MoS2) films were newly demonstrated. In contrast with metal contacts, the surface of the TiSi2 bottom-contact was cleaned by using an ammonia and hydrogen peroxide mixture (APM) before MoS2 deposition, because the TiSi2 film has high oxidation resistance. In order to extract the contact resistance, a transmission line model device was fabricated. A two-order reduction in the contact resistance was achieved by a post-annealing at 650 °C in forming gas ambient (3% H2 in N2). This reduction was attributed to selective titanium diffusion from bottom contact into the MoS2 film. The TiSi2 contact is thus speculated as a candidate for a practical contact material in MoS2 devices.