Imaging the depletion zone in a Si lateral pn junction with scanning tunneling microscopy

Scanning tunneling microscopy (STM) and spectroscopy are used to characterize a lateral pn junction fabricated on a silicon (100) surface. STM images show both an electronic feature and a structural trench at the edges of the ion-implanted p-type regions. The electronic feature widens 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 series of nonequilibrium metal-insulator-semiconductor diodes formed with a semiconductor of spatially variable carrier density. (C) 1998 American Institute of Physics. [S0003-6951(98)01225-X].