SiSiGe n -type resonant tunneling diodes fabricated using in situ hydrogen cleaning

Abstract

In situ hydrogen cleaning to reduce the surface segregation of n -type dopants in SiGe epitaxy has been used to fabricate SiSiGe resonant tunneling diodes in a joint gas source chemical vapor deposition and molecular beam epitaxial system. Diodes fabricated without the in situ clean demonstrate linear current-voltage characteristics, while a 15 min hydrogen clean produces negative differential resistance with peak-to-valley current ratios up to 2.2 and peak current densities of 5.0 A cm2 at 30 K. Analysis of the valley current and the band structure of the devices suggest methods for increasing the operating temperature of SiSiGe resonant tunneling diodes as required for applications. © 2007 American Institute of Physics.