Fabrication of point contacts by FIB patterning

¹ Department of Physics, The University of Texas at Austin, Austin, TX, 78712, USA
² Center for Nano- and Molecular Science and Technology, The University of Texas at Austin, Austin, TX, 78712, USA
³ Texas Materials Institute, The University of Texas at Austin, Austin, TX, 78712, USA

Corresponding author: bogorman@physics.utexas.edu

Received: 27 May 2009
Accepted: 13 October 2009
Published online: 26 November 2009

Abstract

We describe a new technique for the fabrication of point contacts using a focused ion beam (FIB) patterning. After sample coverage with a thin insulating layer (SiO), an FIB is used to mill a 100-nm-diameter hole through the insulator. Electrical contact to the sample is then made in-situ by filling the hole with a metal (Pt) using the ion beam assisted chemical vapor deposition capability of our FIB system. We have demonstrated the use of two such contacts (as an emitter and collector) in a transverse electron focusing (TEF) experiment. The contacts were made to a single crystal of bismuth, ballistic electrons were injected into the crystal through the emitter contact and then focused onto the collector by a magnetic field. We see the expected voltage peaks at the collector as a function of the applied magnetic field. Temperature dependent TEF measurements provided direct information about relaxation time of conduction electrons.