Schottky barrier engineering with a metal nitride–double interlayer–semiconductor contact structure to achieve high thermal stability and ultralow contact resistivity

Abstract

A new contact structure of a metal nitride-double interlayer-semiconductor structure with high thermal stability and ultralow contact resistivity is developed as a next-generation contact scheme via application of interface engineering. As conventional metal–interlayer–semiconductor structures exhibit degradation under thermal stressing owing to the intermixing of materials, three approaches for achieving enhanced thermal stability and ultralow contact resistance are applied. First, a metal nitride with high thermal stability and low reactivity is used as the contact metal. Second, a material with high crystallization temperature is used for the interlayer to prevent the grain boundary diffusion of metal through the interlayer. Lastly, a double interlayer structure is adopted to reduce the Schottky barrier height by utilizing the dipole effect. The corresponding contact was demonstrated to successfully sustain its structure after annealing of 550 ℃. Moreover, it exhibited a specific contact resistivity of 2.20 × 10−8 Ω·cm2, which is a reduction of ~198× and ~2.72× to those of the metal–semiconductor structure and the metal–interlayer–semiconductor structure, respectively. The proposed contact structure and interface engineering techniques in this study provide a valid method to achieve high thermal stability while maintaining low contact resistivity, which is a priority requirement for the emerging nanoscale technology.