A QUANTUM-WELL INVERSION CHANNEL HETEROSTRUCTURE AS A MULTIFUNCTIONAL COMPONENT FOR OPTOELECTRONIC INTEGRATED-CIRCUITS

An approach to optoetectronic integration utilizing a universal heterostructure with a single GaAs quantum-well active region is presented. The inversion channel forms the basis of a heterojunction field-effect transistor, a lateral current injection laser, a field-effect modulator, and a waveguide photodetector by simple reconfiguration of the electrodes and device geometry. The fabrication technology has been developed for GHz bandwidth applications by utilizing ion implantation techniques for interdevice electrical isolation and surface planarization, and reactive ion-etching to realize a self-aligned transistor based heterostructure. The 1 mum gate length single quantum-well heterojunction field-effect transistor is demonstrated with a near-ideal threshold voltage of - 0. 1 V and source input resistance limited transconductance of 92 mS/mm. The 1 mum gate-length heterojunction field effect photodetector is demonstrated with a responsivity of 0.16 A/W, external quantum efficiency of 0.35, and test-laser limited rise time of 100 ps. The 10 mum x 400 mum heterojunction field effect laser is demonstrated with threshold current density of approximately 1 kA/CM2. The 10 mum x 400 mum heterojunction field effect modulator is demonstrated with a contrast ratio of 8.1 for an applied bias change of 2.5 V. The design, fabrication, and characterization of these heterostructures will be discussed in the light of optoelectronic integration, and the implementation of ion implantation disordering to realize low-loss self-aligned waveguides for on chip signal routing. The ultimate performance of the devices using a GaAs quantum well will be considered, and also the development of this technology for improved performance using strained InGaAs wells.