AlGaN/GaN Characterization and Associated Processing and Packaging Technologies

Aluminum Gallium Nitride is a very important material for both electronic and optoelectronic applications. Its use in high power HEMTs and Ultraviolet laser diodes give it a prominent position in devices important to defense and commercial applications of the future. Determination of the characteristics of the material and processing it into a device are as important as the basic physical parameters in device production. We present a study of a sampling of the processes necessary in production of Aluminum Gallium Nitride based devices. We present two sections on the characterization of AlGaN, and related materials, by both Raman Scattering Spectroscopy and Variable Angle Spectroscopic Ellipsometry. These analyses give us data on the percentage of Aluminum in the sample, which is vital to the determination of emission wavelength, and also the refractive indices of the material, which is crucial to the design and modeling of the devices. We also present two sections on processing technologies crucial to the production of laser diodes, Inductively Coupled Plasma Etching and eutectic bonding of laser diodes. Plasma etching is a vital process step as rough, isotropic etching will prevent the devices from functioning. Proper bonding of the laser diode is crucial to the long term operation of optoelectronic devices. Finally, in the appendices, we present some background material on the design considerations for laser diodes.