ON THE VOLTAGE STABILITY OF LATERAL BARRIERS IN IN-PLANE-GATED STRUCTURES

Lateral barriers in a two-dimensional electron gas were fabricated by laser-induced doping of GaAs/AlGaAs quantum well structures. The barri er heights of these insulating lines were analyzed as-a function of vo ltage by temperature-dependent current measurements. The barrier heigh t saturates for large bias voltages. This is connected with surprising ly high breakdown voltages of the sub-mu m lateral barriers. We propos e a model for in-plane-gated structures which can explain these effect s by taking into account surface leakage currents and surface charges. The lateral band diagram and the barrier height as a function of volt age were calculated self-consistently using this model. The model and the calculations are in good agreement with experimentally determined barrier heights, depletion lengths, and time-dependent leakage current s. (C) 1996 American Institute of Physics.