Output characteristics of stacked CMOS-type active pixel sensor for charged particles

A stacked CMOS-type active pixel sensor (SCAPS) for charged particles has b een developed. The SCAPS is an integral-type detector that has several adva ntages over conventional systems, including two-dimensional detection, wide dynamic range, no insensitive time, direct detection of charged particles and a high degree of robustness. The output characteristics of the SCAPS fo r incident charged particles has been analysed both theoretically and exper imentally. The relationships between the output voltage of the SCAPS and th e number of incident charged particles were formulated by including correct ions for the non-ideal characteristics of transistors in a pixel. The fluct uation of output characteristics of the SCAPS was evaluated experimentally by irradiation of secondary 4.5 keV Si+ ions generated by SIMS. The functio n was used to determine the number of incident ions into each SCAPS pixel w ithin twice the statistical error. The SCAPS is useful as a two-dimensional detector for microanalysis, such as stigmatic SIMS. Copyright (C) 2001 Joh n Wiley & Sons, Ltd.