Ac Surface Photovoltages in Strongly-Inverted Oxidized p-Type Silicon Wafers^*

Abstract

Surface photovoltages in Si wafers excited with a chopped 559 nm-wavelength photon beam are analysed using a new half-sided junction model. In this model, the wafer surface with the depletion layer is considered to be one half of the p-n junction. Chopping frequency ranges from 2 Hz through 20 kHz. Four 76 mm-diameter p-type Si wafers having resistivities of 260, 92, 17 and 1.0 mΩ m are used after forming 360 nm-thick wet-oxide layer on their front surfaces. In these wafers, photovoltage increases with resistivity. In three high-resistivity wafers with strongly-inverted surfaces, the inversion capacitances and conductances limit the photovoltages at low frequencies. The obtained inversion time-constant is 7 s for the 17 mΩ m wafer.

Surface photovoltage phenomena: theory, experiment, and applications

“…These may include minority and majority carrier transport, depletion and inversion layers, surface states, etc. [94], and may be lumped into an equivalent resistance, R eq , and capacitance, C eq . Expressions for the different resistance and capacitance components are obtained by appropriate modi®cations of the derivations presented above, which take the time-dependence into account.…”

Au/N‐type Si Schottky‐barrier contact and oxidation kinetics in Au‐contaminated and thermally oxidized N‐type Si (001) surfaces

“…The frequency-dependent AC SPV was measured with a new instrument, developed in-house, [5] on the basis of the theory reported by Munakata et al [7,8] This instrument evaluates charged states by irradiating the wafer with a blue PB (with a wavelength peak at 470 nm) and an optical power of the order of microwatts. The incident PB power was actually adjusted to 2.5 µW.…”

“…In the stronginversion case, the AC SPV is inversely proportional to frequency (1/f , f : frequency). [7] When n-type Si wafers having hydrophobic surface were rinsed in an Au aqueous solution, an occurrence of AC SPV was observed because of the deposition of Au on the Si surface, [9] demonstrating that depleted and/or weakly inverted layers can be formed at the n-type Si surface. On the basis of the frequencydependent AC SPV, a band diagram of Au/n-Si Schottky contact was proposed and the Au/n-Si Schottky barrier was calculated to be 0.73-0.76 eV, [9] which is in good agreement with the previously reported result (0.79 eV).…”

Communication: Enhancement of dopant dependent x-ray photoelectron spectroscopy peak shifts of Si by surface photovoltage

“…[25][26][27] A simplified and more chemical interpretation is as follows. An n-doped sample is electrically neutral but has more or less free and delocalized electrons, while a p-doped sample has the opposite (i.e., holes).…”

“…Such differences must be attributed to the additional oxidesemiconductor interfaces introduced. It is well known and established that electrons are injected from the oxide to the silicon so that the oxide side of the interface is positively charged for a p-type silicon, [25][26][27] as shown schematically in Figure 5(a). Hence the overall band-bending is additive (p-type + oxide), resulting in a larger shift upon illumination.…”