LITHOGRAPHIC POINT CONTACTS FOR TRANSVERSE ELECTRON FOCUSING IN BISMUTH

An electron-beam lithography technique for fabricating submicron point contacts to planar surfaces of bulk samples is described. We have dem onstrated the technique by creating a linear array of paint contacts, oriented along the bisectrix axis of a bismuth single crystal, which a ct as emitters and collectors in multiprobe transport measurements. In a transverse electron focusing geometry, we find the expected series of periodic voltage peaks as a function of applied magnetic field at l ow temperatures. The lithographically fabricated contacts offer advant ages over conducting-needle probes in electrical integrity, thermal ro bustness, lack of damage to the contact site, ability to make multiple submicron contacts with <10 mu m separations and ability to align the contacts precisely along crystallographic axes. (C) 1996 American Ins titute of Physics.