IMAGING THE DEPLETION ZONE IN A SI LATERAL PN JUNCTION WITH SCANNING-TUNNELING-MICROSCOPY

Scanning tunneling microscopy (STM) and spectroscopy are used to chara cterize a lateral pn junction fabricated on a silicon (100) surface. S TM images show both an electronic feature and a structural trench at t he edges of the ion-implanted p-type regions. The electronic feature w idens with applied reverse bias indicating that it is associated with the depletion zone. The electronic feature and its voltage dependence are described qualitatively by modeling the tip-junction system as a s eries of nonequilibrium metal-insulator-semiconductor diodes formed wi th a semiconductor of spatially variable carrier density. (C) 1998 Ame rican Institute of Physics. [S0003-6951(98)01225-X].