Accurate Growth of Submilliampere Threshold Current Vertical Cavity Surface Emitting Laser using Diode Laser Reflectometry in a Molecular Beam Epitaxy System

Vertical cavity surface emitting lasers (VCSELs) and resonant cavity detectors are of great interest for optical communications applications. In order to obtain high performance devices with high yield, the epilayer thickness and growth rate must be controlled to within ±1.5 %. Conventional molecular beam epitaxy calibration method such as reflection high energy electron diffraction (RHEED) and ion-gauge beam flux measurements are limited to an accuracy of a few percent. To achieve higher accuracy, various in situ optical techniques have been investigated for growth rate calibration [l]-[2] and for real time growth control [3]-[4]. The former is desirable because of its versatility and cost-effectiveness.