Technology

A Promising New Valved Source for Ga or In Evaporation

A new valved source for evaporation of Ga or In has been demonstrated. It’s performance in terms of controlling the group III flux has been shown to be very good to excellent in terms of response time (2-3 seconds), reproducibility (~1%), stability (~0.1%), and shut-off ratio (at least 30:1). In addition, this cell has produced GaAs, InGaAs, and InAlAs layers with material quality comparable to other state-of-the-art sources in terms of uniformity, surface morphology, background doping, carrier mobility , and PIN device performance. Finally, it has been demonstrated that the graphite-based material used for the crucible and valve in this source do not generate any extra carbon doping compared to the usual Pyrolytic Boron Nitride (PBN) based crucibles. Full Article >

The TitanTM Effusion Cell: The Latest in Group III Effusion Cell Design

The TitanTM effusion cell has been developed by E-Science to give MBE growers added performance by providing lower defect counts, improved uniformity, high capacity, reduced shutter transients, and a shorter source conditioning time. This sealed two-piece graphite crucible design provides distinct advantages over one or two piece PBN versions. Operation and maintenance of the cell and crucible is appealing with the ability to run on one filament, accept a single piece of charge material, and operate over multiple campaigns. The TitanTM cell and crucible set offer superior performance over others available on the market today. Full Article >

The E-Science MOCVD Substrate Heater for Nitride Applications

Nitride applications have accounted for the majority of the new MOCVD tool purchases over the past 5 years. These applications have introduced much greater demands on the performance of the MOCVD tools than was required for the more traditional As/P based devices. In particular, growth temperatures for nitrides can reach over 1200 C. These temperature requirements, coupled with the exposure to reactive gasses, put strain on the substrate heater requiring careful design and material selection. In this paper, we present a new heater that has achieved outstanding results and greatly increased lifetimes over other manufacturers’ heaters. Full Article >