Comparison of the effects of different lateral boundary conditions on transport in resonant tunneling diodes

Small resonant tunneling diodes (RTDs) will be required to achieve high speed with low power dissipation. We have modeled transport in RTDs including lateral boundary conditions, and find that the peak-to-valley-current ratio of small RTDs can be significantly degraded. For an example in which p-type regions were used to restrict the electron current to the central 200 nm of the RTD, the peak-to-valley-current ratio was reduced to 2.8:1 from 26:1 calculated for a large area device. Similar, but smaller, effects were calculated when semi-insulating regions (as might be produced by a damage implant) were used to define the device area.