Monte Carlo Simulation of Boundary Scattering Effects for Power MOSFET Performance

Miniaturization of microelectronic devices has lead to many new issues not seen in larger structures, such as hot carrier effects and interfacial effects. In power MOSFETs, degradation of the transconductance can occur over the lifetime of a device. This decrease in performance is a result of hot carriers in the channel region scattering at a Si/SiO₂ interface that has been passivated with hydrogen. Eventually hot carriers liberate the hydrogen, leaving silicon bonds with an entirely different scattering cross section. The current work presents a Monte Carlo simulation of carrier transport in silicon near an interface. Scattering parameters at the interface are parameterized and studied. It was found that electron mobility, which is proportional to transconductance, is a function of the energy loss rate and type of scattering at the interface. Results indicate that dangling bonds and H-Si bonds can be characterized by different scattering mechanisms.