Computer Study of Bulk GaAs Devices with Random One-Dimensional Doping Fluctuations

Abstract

Computer calculations have been performed in order to investigate the influence of one‐dimensional random doping fluctuations and localized inhomogeneities on the performance of bulk GaAsoscillators. For the doping fluctuations assumed it was found that accumulation layers dominate in subcritically doped samples (n 0×L<1012 cm−2) while dipole layers always form in samples doped above the critical level. Five different modes of oscillation are described and defined with the help of a mode chart. Special attention is paid to the ``quenched multiple‐dipole'' mode, which is difficult to obtain if localized inhomogeneities such as dislocations or doping gradients are incorporated in addition to the random fluctuations. It is concluded that a series‐connection of accumulation‐mode devices, which are not sensitive to doping fluctuations, provides an attractive approach to microwave or millimeter‐wave oscillator design.