n-type Si/SiGe resonant tunnelling diodes

Resonant tunnelling diodes (RTDs) have been fabricated using Si/SiGe heterolayers which demonstrate room temperature performance comparable to III-V technology. Peak current densities up to 282 kA cm(-2) with peak-to-valley current ratios (PVCRs) of 2.4 have been demonstrated at room temperature in devices with dimensions of 5 x 5 mum. Scaling the device size demonstrates that the peak current density is inversely proportional to the device area. It is suggested that this is related to thermal limitations in the device structure. Estimates are also produced for the maximum frequency of oscillations of the diodes which suggest that oscillators may operate with speeds comparable to III-V diodes. (C) 2002 Elsevier Science B.V. All rights reserved.