Formation of Nitride Laser Diode Cavities with Cleaved Facets By Wafer-Bonding and Laser Lift-Off

• Main Authors: Wen-Chien Yu, 游文謙
• Other Authors: Wei-I Lee
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/85145511657750186359

碩士 === 國立交通大學 === 電子物理系所 === 95 === Smoothly cleaved facets with high reflectivities have been demonstrated on GaN laser diodes after the devices were transferred onto GaAs substrates. The GaN based laser diode structure was first fabricated by metal organic chemical vapor deposition (MOCVD) on c-plane sapphire substrates. Inductively coupled plasma (ICP) etch was applied to define GaN laser stripe patterns. The samples were then mounted onto thin GaAs substrates using wafer-bonding technology. Various types of bonding metals, bonding pressures, and bonding temperatures have been attempted in the process. Laser lift-off (LLO) technique was applied to remove the original sapphire substrate and hence transfer the GaN based laser diodes structure onto GaAs substrates. Since the cubic substrates have well-defined cleaved facet, the GaN based laser diodes structures bonded onto the substrates also formed smooth facets after cleavage. The cleaved facets of GaN laser diodes have been characterized using atomic force microscopy (AFM) with less than 3 nm roughness. Theoretical calculations indicated that a rms roughness of less than 4 nm is required to obtain the reflectivity of greater than 90% for the laser cavity. The present study demonstrated the feasibility of transferring GaN laser structures onto other more appealing substrates for formation of laser cavities.