Plasma etching of antimonide based III-V semiconductor materials and device structures

Antimonide based optoelectronic devices are of significant interest for a wide range of applications including infrared emission and detection, high speed electronics and thermophotovoltaics. To the best of our knowledge, thorough studies in the area of dry etching of antimonides have not been performed which address the issue of damage associated with plasma etching of antimonides. This thesis addresses the need for developing etching recipes for antimonides with a low damage plasma etch for processing sensitive III-V based photodiodes. A new plasma mixture based on mixed BCl 3/Cl2/Ar and CH4/H2 has been successfully developed and shown to provide high etching rates with minimal or no damage to the etched surfaces. Devices fabricated using this plasma etching recipe demonstrated superior electrical and optical characteristics compared to previously reported plasma chemistries or widely used wet etches.; High density plasma etching using electron cyclotron resonance (ECR) and inductively coupled plasma (ICP) reactors produced rapid (greater than 500nm/min), anisotropic etching by using the BCl3/Cl2/Ar/CH 4/H2 chemistry. The low power plasma using the BCl3 /Cl2/Ar/CH4/H2 recipe produced rapid etching with a smooth surface morphology and good anisotropy. Optimize ranges for the plasma composition and parameter ranges are reported.; Two different types of photodiodes were fabricated and characterized, namely Zn diffused GaSb pn junction diodes and antimonide based GaSb/InAs superlattice (ASL) photodetectors. The pn junction diodes showed significantly improved characteristics for the BCl3/Cl2/Ar/CH 4/H2 etched samples compared to those fabricated with Cl 2/Ar or wet chemistry. The ASL photodetectors showed similar trends. Electrical and optical characteristics of the ASL devices fabricated with a low power dry plasma etch mixture of BCl3/Cl2/Ar/CH 4/H2 were comparable in their performance to that of the wet etched devices. Leakage currents densities for the wet etched and low power plasma BCl3/Cl2/Ar/CH4/H2 etched diodes are on the order of 10-3A/cm2. Additional comparative device characteristics including RoA and eta are reported, and show devices fabricated using alternative gas mixtures or increased power performed significantly worse.; While more research is still required in the area of antimonide plasma processing, the results of current research are extremely encouraging and provide motivation continued study of dry etch processing for antimonide based devices.