GaAs optoelectronic integrated circuit with vertical field-effect transistor using selective metalorganic chemical vapor deposition

Abstract

Most efforts in this area of optolectronic Integrated circuits (OEICs) are actually aimed at optical communication OEICs are also expected to be useful for optical interconnection between boards and/or chips, and even within a chip. Recently vertical cavity surface-emitting laser diodes with high-reflectance stacked mirrors have drawn attention for various applications such as parallel optical signal processing and high-speed optical interconnections. In this thesis, a new vertical OEIC structure is proposed and fabricated by the selective MOCVD technique. This vertical OEIC has a stacked planar layer with a surface-emitting LED and a vertical transistor. The embedded Schottky metal between the epitaxial GaAs layers is employed as a gate electrode of the vertical driver FET. For the device process, the selective area growth of GaAs with semiconductor-metal-semiconductor (SMS) structures using pulsed-mode operation of MOCVD, which controls the flow of TMG at regular intervals, is studied experimentally. GaAs is selectively grown over 3μ -period tungsten gratings on (100) GaAs substrates. Tungsten gratings are masked with $SiO_2$ for the selective growth and it is possible to have good GaAs growth over tungsten gratings without keeping substrate temperature high and the growth rate low. The ideality factor and the barrier height of the W-GaAs Schottky diode in-situ annealed nuder the growth conditions show slight degradation with increased growth time. Using double crystal X-ray diffractometer and auger electron spectroscopy analysis, it is shown that the slight interdiffusion of tungsten W and GaAs and the out-diffusion of Ga takes place. Two-dimensional numerical simulations of the vertical FET structure with PIECES-2B are performed in order to get more insight into the details of operation of this device. The characteristics of the FET are divided into a pentodelike region and a triodelike region depending on design parameters such as doping concentration and ...