Fabrication of resonant-tunneling diodes by Sb surfactant modified growth of Si films on CaF/sub 2/Si

Abstract

Molecular beam epitaxy growth of Si thin films on CaF/sub 2//Si(111) substrates has been studied. A surfactant-modified solid-phase epitaxy method, where the room temperature Si deposition was followed by annealing under Sb flux, resulted in a continuous, smooth epitaxial crystalline Si film with a sharp (/spl radic/3/spl times//spl radic/3)R30/spl deg/ reconstruction and a surface roughness of 0.15-nm rms for a 2.8-nm Si thin film. This growth technique was used to fabricate CaF/sub 2//Si/CaF/sub 2/ double-barrier resonant tunneling diodes in SiO/sub 2/ windows patterned on Si(111) substrates. A negative differential resistance (NDR) peak was found at /spl sim/0.35 V at 77 K, and the current density at the NDR peak was estimated to be 3-4 orders of magnitude higher than in earlier reports.