Exceptionally stable vapor delivery of trimethylindium under intense OMVPE growth conditions

Abstract

Trimethylindium (TMI) is the preferred precursor for the deposition of indium containing layers by organo-metallic vapor phase epitaxy (OMVPE) because of its higher vapor pressure and its ability to transport readily into vapor phase. However, maintaining the stability of TMI's molar flux during the OMVPE still remains as a challenge to crystal growers, despite the development of numerous solutions to resolve this issue. In this study, we report excellent results of stable TMI delivery, achieved under aggressive conditions of pressure, temperature and flow. Most importantly, these results are achieved by using 100% (or standard) cylinder fill capacities for the first time, a strategy that differentiates this research from all prior work on TMI delivery. Exceptionally stable mass transport of TMI has now become possible with innovative improvements to our patented cylinder design (Uni-Flo™ cylinder). TMI evaporation rates are studied over an extensive range of operating parameters currently employed in OMVPE, e.g. the flow rates ranging between 100 and 1000 sccm, bath temperatures between 17 and 30 °C, and pressures in the range 300–1000 mbar. Significant improvements in delivery and an excellent reproducible dosimetry of TMI are realized in conjunction with the utilization of TMI at levels as high as >95%, before any noteworthy concentration decline becomes apparent. Our study thus shows that by using the Uni-Flo™ cylinder with these proprietary improvements, a reproducible vapor phase transport of >95% TMI is achieved, with exceptionally stable and higher molar flux of TMI over an extensive range of operating parameters and throughout the cylinder life.