Hole conduction characteristics of strained Si1−xGex/Si resonant tunneling diode

We study the hole conduction characteristics of p-type strained Si1−xGex/Si double-barrier resonant tunneling diodes (RTD). By extensive theoretical calculation of the 6×6k·p model together with the deformation potential to account to the strain in Si1−xGex layer, we have obtained the hole conduction characteristics which explains the recent experimental results of Han et al. (J. Cryst. Growth 209 (2000) 315), where it was reported that the low-bias resonance peak becomes dissolved by increasing the device temperature. The calculated I–V characteristics exhibits several resonance peaks, and the current density varies drastically (the second-resonance peak current density is higher than the first one by a factor of 103). Since only resonance peak having high-enough current density is measurable, low-temperature I–V characterization can only dissolve high-bias resonance. Increasing the device temperature, low-bias resonance becomes significant due to thermal excitation.