A novel /spl delta/-doped GaAs/lnGaAs real-space transfer transistor with high peak-to-valley ratio and high current driving capability

A three-terminal /spl delta/-doped GaAs/In/sub 0.25/Ga/sub 0.75/As/GaAs real-space transfer transistor (RSTT) has been implemented by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) for the first time. We carried out an ohmic recess resulting in shallow alloyed contacts, electrically isolated from ohmic electrodes. An undoped low-growth-rate buffer layer was inserted between the collector and barrier to suppress the dopant out-diffusion from the substrate to the barrier. The proposed device with a 5×100 μm
²
emitter channel revealed an extremely sharp charge injection, a broad valley range (>5 V), a high peak-to-valley current ratio up to 430000, and a high current driving capability at room temperature. These characteristics are, to our knowledge, among the highest reported values to date.