Fabricating Hybrid NiSi-Si devices for charge pumping

Hybrid NiSi-Si single electron devices show promise as charge pumps which could be parallelized into a quantum standard of current [1]. However, fabricating the tunable Schottky barrier (SB) between nickel silicide (NiSi) and silicon which controls the pumping outside of industrial level processing environment is difficult. The most demanding processing is maintaining a few 10’s of nanometers of silicon between silicided leads and the silicide dot, deposition of a high-quality oxide, and gates aligned to the gaps. We present our fabrication, measurement, and analysis of tunnel barrier devices to prove the fabrication process. The measured drain-source current is fit by thermionic single and double junction Schottky diode equations. This analysis provides useful information about the energetics (SB height) of devices and gives important parameters for single-electron pumps.

[1]. X. Jehl, B. Voisin, T. Charron, P. Clapera, S. Ray, B. Roche, M. Sanquer, S. Djordjevic, L. Devoille, R. Wacquez, and M. Vinet, Phys. Rev. X 3, 021012, 2013