The photovoltaic observation of semiconductor surfaces

Abstract

Flying-spot scanning images of a chemically etched p-type polycrystalline Si wafer, 60 mm in diameter, are obtained nondestructively using the AC photovoltage excited by a visible photon beam chopped at 2 kHz. The AC photovoltage is concluded to be the surface photovoltage correlated with the native oxide layer. After thermal annealing in N2 ambience at 850 degrees C for 60 min, the surface image drastically changes. This might be due mainly to fixed oxide charge modification and partly to variation in the minority carrier diffusion lengths.

Surface photovoltage phenomena: theory, experiment, and applications

“…As an illustrative simple example, an SPV image of a Si wafer after various treatments is shown in Fig. 28 [222]. Various degrees of surface damage are easily exposed since they affect the magnitude of the obtained SPV signal.…”

Molecular Photovoltaics in Nanoscale Dimension

“…To pick this electrostatic signature, we utilize an auxiliary transparent electrode that acts as a capacitive probe ( Figure 12 ). This probe, proposed by Bergmann in 1932, selectively picks the ac voltage [ 87 ]. Previously, the transparent auxiliary electrode has been used to study the photovoltage generated by the p-n junctions.…”

“…Previously, the transparent auxiliary electrode has been used to study the photovoltage generated by the p-n junctions. This nondestructive no contact method proved to be convenient for the quality control of these junctions before and without equipping them with electrodes [ 87 , 88 ] or for measurement of the lifetimes of the minority charge carriers [ 89 , 90 ]. In those measurements, the ac photovoltage has been generated by a chopped light beam and its amplitude has been measured.…”

An insight into optical beam induced current microscopy: Concepts and applications

“…The screen generated laser of wavelength 500 nm, which enabled investigation of different photo‐processes in different samples with a resolution of ~1–2 μm. Similarly, Munakata et al (Munakata et al, 1982; Munakata & Matsubara, 1983) and Kinameri et al (Kinameri et al, 1988) utilized flying‐spot scanners that used visible and near infrared CRTs to emit photon beams chopped at a frequency of 2 kHz. Notably, the group detected the generated ac photovoltage from Si wafer, solar cell PN‐junction, non‐uniformly ion‐implanted junction, and partly‐deep junction capacitively without using any metal electrode directly in contact with the front surface of the semiconductor wafer.…”