Scanning capacitance microscopy (SCM) and Kelvin probe force microscopy (KPFM) are used to image the electrical structure of a silicon pn junction under applied bias. With SCM, the carrier density inside a diode is imaged directly. With KPFM, the surface potential distribution of an operating diode is measured, revealing different behavior from that in bulk. The surface potential drop is extended deep into the lightly p-doped region at reverse bias, reflecting the existence of the surface space-charge region as confirmed by the numerical simulation.

Electrical characterization of an operating pn-junction diode is performed with scanning capacitance microscopy ͑SCM͒ and Kelvin probe force microscopy ͑KPFM͒ with submicron scale resolution. We image the spatial distribution of the carrier density inside a diode with SCM and the potential distribution on the surface of the operating diode with KPFM. The surface potential distribution measured at reverse bias is different from that in bulk. The potential drop is extended deep into a lightly p-doped region at reverse bias. The positive fixed oxide charge of 1 -2ϫ10 11 /cm 2 would explain the modified potential drop: A known detrimental effect in such a device. The potential distribution at forward bias is nearly bulklike. The potential drops only near the metalsemiconductor junction.

To measure the thickness of SAMs, ellipsometry using a p-polarized laser beam is commonly used, which provides indirect information on the entire surface. Herein, a direct method for estimating the thickness of multilayered thiolated-Au films using atomic force microscopy (AFM) oxidation is described. When a bias voltage is applied to thiolated-Au films, the sulfur-gold bond is readily cleaved via a desorption procedure, and the nano-explosion through electron tunneling occurs at the nano-contact between the probe tip and surface. A multi-step uncovered layer is obtained, which can be used to estimate the thickness of each layer (organic and gold). This procedure is referred to as "electronic punch" of AFM, and is applicable to thiolated-Au films.