Quantum-aperture formation in a quasi-ballistic MESFET by neutron irradiation

The effect of neutron irradiation with a fluence reaching 5 × 10 15 cm-2 on a quasi-ballistic MESFET is studied theoretically and experimentally. A marked improvement is observed in the device performance; it is attributed to quantum effects. The experimental results are interpreted by the Monte Carlo simulation of defect formation and carrier transport in the channel of irradiated devices. It is shown that the positive effect of irradiation may be linked to the transformation of the channel into a set of quantum-size gaps (short quantum wires) between radiation-defect clusters. The higher degree of control over the drain current should result from the influence of the gate voltage on the gap diameter (and hence on the electron energy levels associated with the gaps). © MAIK "Nauka/Interperiodica" 2005.