Silicon quantum point contact with aluminum gate

Fabrication and electrical properties of silicon quantum point contacts are reported. The devices are fabricated on bonded silicon on insulator (SOI) wafers by combining CMOS process steps and e-beam lithography. Mobility of 9000 cm(2) Vs(-1) is measured for a 60 nm-thick SOI film at 10 K. Weak loca lization data is used to estimate the phase coherence length at 4.2 K The p oint contacts show step like behaviour in linear response conductance at 1. 5 K. At 200 mK universal conductance fluctuations begin to dominate the con ductance curve. The effective diameter of quantum point constrictions of th e devices are estimated to be 30-40 nm. This estimate is based on TEM analy sis of test structures and AFM images of the actual device. (C) 2000 Elsevi er Science S.A. All rights reserved.