[1Cp01-07] Surface Analysis/Applied Surface Science/Evaluation Technique (ASS)

[1Cp02] Measurement of interface state density on pn-paterned Si surface using high- and low-frequency Kelvin probe force spectroscopy

*Yasuhiro Sugawara¹, Ryo Izumi¹, Masato Miyazaki¹, Yan Jun Li¹ (1. Graduate School of Engineering, Osaka University)

Information on the energy spectrum of the interface state density is important for actual semiconductor device evaluation, and there is a need to develop a method for obtaining such physical quantities. Here, we propose high—low frequency Kelvin probe force spectroscopy (high—low frequency KPFS), an electrostatic force spectroscopy method using high- and low-frequency AC bias voltages to measure the interface state density inside semiconductors. We derive an analytical expression for the electrostatic forces between a tip and a semiconductor sample in the accumulation, depletion, and inversion regions, taking into account the charge transfer between the bulk and interface states in semiconductors. We show that the analysis of electrostatic forces in the depletion region at high- and low-frequency AC bias voltages provides information about the interface state density in the semiconductor band gap. As a preliminary experiment, high-low frequency KPFS measurements were performed on ion-implanted silicon surfaces to confirm the dependence of the electrostatic force on the frequency of the AC bias voltage and obtain the interface state density.