TUNNELING AND IMPACT IONIZATION AT HIGH ELECTRIC-FIELDS IN ABRUPT GAAS P-I-N STRUCTURES

GaAs p-i-n structures with very abrupt doping transitions and differen t lengths of the quasi-intrinsic zone have been fabricated by molecula r beam epitaxy technology. For structures with ultra-thin intrinsic zo nes, tunnel currents were determined experimentally up to electric fie lds of 1.9 MV/cm, in good agreement with a modified Kane model. The di fference of calculated tunnel current and measured total current in st ructures which also perform impact ionization is used to fit a Monte C arlo simulation program at high electric fields. Resulting idealized h omogeneous-field ionization rates are given which are experimentally v erified up to fields of 1.3 MV/cm. (C) 1997 American Institute of Phys ics.