Planar electron-tunneling Si/Si0.7Ge0.3 triple-barrier resonant tunneling diode formed on undoped strain-relaxed buffer with flat surface

Abstract

We demonstrated a planar electron-tunneling Si/Si0.7Ge0.3 triple-barrier (TB) resonant tunneling diode (RTD) formed via a channel layer on an undoped strain-relaxed quadruple-Si1−xGex-layer (QL) buffer. Compared with a conventional vertical Si/Si0.7Ge0.3 TB RTD formed on a heavily doped QL buffer, the dislocation density is low, the surface is flat, and the resonance current density is much larger. These observations, together with analyses of current–voltage (I–V) curve fitting to the physics-based analytical expression, suggest that the enhanced I–V characteristics in the planar RTD are related to decreases in the number of crystalline defect states and the structural and potential fluctuations.