Characterization and Optimization of GaAs Contact Resistance

High power lasers such as master oscillator power amplifier (MOPA) lasers face the problem of laser heating as electrical current is pumped through the device. As a result, the joule heating affects the output power and laser efficiency. One major source of joule heating is the contact resistance, which is the resistance at the interface between the metal layer and the semiconductor surface. This resistance would play a crucial role in lowering the power dissipation in semiconductor devices. It is therefore important to characterize the contact resistance by optimization of GaAs IC metallization stack. This thesis will discuss the fabrication and characterization process for GaAs contact resistance measurement using the transfer length method (TLM). The project involved growth of p-epi layer on GaAs surface through metal-organic chemical vapor deposition (MOCVD). Ohmic contacts were patterned and deposited on the GaAs substrate through E-beam evaporation. The effect of variation of metal stack and the layer thicknesses was investigated. Also, different etching and annealing conditions were tested during the process. The results were compared with existing literature, and the process yielding the minimum contact resistance is outlined in the thesis.unpublishednot peer reviewedU of I OnlyUndergraduate senior thesis not recommended for open acces