Monte Carlo study of anisotropic hole velocity overshoot in sub-0.1 μm GaAs devices for complementary circuit applications

In order to evaluate the high-speed and low-power performance of sub-0.1 μm-sized GaAs devices used for complementary circuits, we studied full-band Monte Carlo simulations of high field hole transport in bulk GaAs and one-dimensional p-i-p diodes. We found that the peak hole velocity under an electric field of 100 kV/cm reaches 2.2×10⁷ cm/sec at room temperature, which is about three times higher than the steady-state drift velocity. We also simulated anisotropic hole velocity overshoot effects and demonstrated that the peak velocity with an electric field applied along the 〈100〉 direction is about 30% higher than in other directions, although the saturation velocities are almost the same. In this paper, we discuss the hole velocity overshoot affect on the characteristics of a nanometer-sized device, and present a similar anisotropic dependence on the current drivability of 0.05 μm p-i-p diodes.