This work investigates the effect of Cl 2 / Ar dry etching on p-GaN. The root-mean-square ͑rms͒ surface roughness is measured, and the depth display ͑Bearing analysis͒ is monitored. The current-voltage characteristics of etched p-GaN with Ni ͑20 nm͒ /Au ͑20 nm͒ metallization are studied. Experimental results indicate that the etching rate does not increase significantly with the Cl 2 flow rate at a constant power or chamber pressure. The Bearing ratio data exhibit a much stronger variation with etch conditions, the rms displays the same trend but to a lesser extent.
Ion-implanted GaAs MESFETs with and without extra oxygen implantation have been fabricated, studied and compared. The extra oxygen implantation was employed after the channel implantation to form a high-resistance layer near the surface of GaAs MESFETs and to replace the passivation process. Two different oxygen implantation and annealing conditions were used to study the effect of implanted oxygen on device performance. The device with oxygen implantation and annealing at the same time as channel implantation demonstrated improved transconductance and breakdown characteristics, less frequency dispersion of drain current and good time dependence of drain current at 150 • C in air without sacrificing rf performance.
In this paper, we report a collector-up npn heterojunction bipolar transistor (C-up HBT) which employs a p-type doping buried layer inserted between an extrinsic emitter and a subemitter for current confinement. Fabrication of C-up AlGaAs/GaAs HBTs with a selectively buried layer by metalorganic chemical vapour deposition (MOCVD) regrowth is described. The fabricated C-up AlGaAs/GaAs HBT demonstrates good common-emitter I-V characteristics and a current gain of 18. A systematic analysis is performed to verify the functionality of the p-type doping buried layer using a two-dimensional device simulator. It is found that the p-type doping buried layer should be biased properly to achieve the high efficiency of current confinement. And the HBT with a large E V at the base-emitter heterojunction is preferred for the proposed C-up HBTs to reduce hole back-injection.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.