This paper presents a new technique to build MOS dosimeters using unmodified standard CMOS processes. The devices are n-channel MOS transistors built with the regular Field Oxide as a thick radiation-sensitive gate. The devices were fabricated in two different commercial m CMOS processes, gate oxide thicknesses of nm and nm. Responsivities up to 4.4 mV/rad with positive bias, and 1.7 mV/rad with zero gate bias were obtained in the thicker oxides. The effect of charge trapped in the oxide and interface states on the shift in the threshold voltage are analyzed.

Al2O3-based dielectrics are currently considered as promising materials to use in nonvolatile memories. The electron trap density in this material is much higher than in conventional SiO2, being their characteristics critical for the application. Conventional capacitance-voltage (C-V) techniques were used to study the main effects of the electron traps on the electrical characteristics of MOS capacitors with atomic layer deposited Al2O3 as insulating layer. More detailed information about the trapping kinetics was obtained through the study of the constant capacitance voltage transient. Two different types of traps were found. One is responsible for the instabilities observed in C-V measurements, the other has characteristic trapping times three orders longer. A physical model is presented to explain the observed trapping kinetics exhibiting good agreement between experiments and simulations. The energy levels of the studied traps were determined at 2.2 and 2.6 eV below the Al2O3 conduction band, with densities of 2.9 × 1018 cm−3 and 1.6 × 1018 cm−3, respectively.

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