Imaging of a silicon pn junction under applied bias with scanning capacitance microscopy and Kelvin probe force microscopy

Scanning capacitance microscopy (SCM) and Kelvin probe force microscopy (KP FM) are used to image the electrical structure of a silicon pn junction und er applied bias. With SCM, the carrier density inside a diode is imaged dir ectly. With KPFM, the surface potential distribution of an operating diode is measured, revealing different behavior from that in bulk. The surface po tential drop is extended deep into the lightly p-doped region at reverse bi as, reflecting the existence of the surface space-charge region as confirme d by the numerical simulation. (C) 2000 American Institute of Physics. [S00 03-6951(00)03427-6].