Optoelectronic devices with embedded semiconductor-metal-semiconductor structure by selective liquid phase epitaxy

Abstract

The GaAs can be used in the electronic devices and the optical devices. To exploit those properties in one chip, the electronic devices and the optical ones are integrated. The integrated chip is called as an optoelectronic integrated circuit (OEIC). To use the OEIC, the different process steps from the structural diversities of the integrated devices should be selected. As a possible solution, the semiconductor-metal-semiconductor structure was suggested in this thesis. This structure has been used in the permeable base transistor up to now. At first, the SMS structure was implemented by the selective liquid phase epitaxy (LPE) method. The increased as supply from the masked region augmented the lateral growth of GaAs relative to the vertical one. This enabled the growth of GaAs over the tungsten stripes. After the growth, the cross section was observed by the SEM. To confirm the possible degradation of W on GaAs, the annealing study was done under the same conditions of the SLPE. A serious interdiffusion was observed by the SEM, X-ray and AES analyses. Even though the mechanical changes in W after annealing, the Schottky junction of W on GaAs held its rectifying property. This made it possible to fabricate the optoelectronic devices with the SMS structure. As applications, the photodetector with the embedded Schottky electrode was proposed and fabricated. It could show the more enhanced use of the active area than the conventional MSM-PD. The conventional one has the Schottky electrodes on top of the active area so that the volume is partially shadowed. The suggested SMS structure can be used in OEIC. It can be vertically integrated as an electronic devices. By this integration scheme, the OEIC can control the optical output by applying a gate bias to the gate. And more effective coupling between the electronic device and the optical one is expected. To testify the scheme, a VFET was fabricated. With 3$mu$m period tungsten grating, the transistor operated in ...