The effect of molecular‐beam‐epitaxial growth conditions on the electrical characteristics of In0.52Al0.48As/In0.53Ga0.47As resonant tunneling diodes

Abstract

We have investigated the dependence of the performance characteristics of In0.52 Al0.48As/ In0.53 Ga0.47 As resonant tunneling diodes upon molecular‐beam‐epitaxial growth parameters. The roughness of the growth front, leading to intrawell‐size fluctuations and the V/III flux ratio at a fixed growth temperature are found to be important parameters affecting the performance of these devices. By means of a simple model, we have semiquantitatively related the peak current to the interface roughness. Defects and traps in the In0.52 Al0.48 As barriers, on the other hand, produced partially by nonoptimal V/III flux ratios, may produce shunt paths for tunneling, again reducing the resonant tunneling current peak‐to‐valley ratio. Under optimum growth conditions we have measured current peak‐to‐valley ratios of 6.1 and 21.6 at 300 and 77 K, respectively. These are the best values reported so far for this heterostructure system.