Capacitance-Voltage Measurement for Characterization of a Metal-Gate MOS Process

A procedure to characterize oxide and conductor layers that are grown or deposited on semiconductor can be done by studying the characteristics of a MOS capacitor that is formed of the Conductor (metal)–InsulatorSemiconductor layer. For a capacitor formed of MetalSilicon dioxide-Silicon layers with an oxide thickness of 628Å (measured optically), some of the calculated material parameters were far from the expected values. Those errors might be due several factors like a possible offset capacitance of the probes due to improper contact with the wafer which is measured using Visual Engineering Environment Programming (VEE Pro), a possibility of undesired deep depletion or due to hysteresis error. To solve these problems, In this paper it is suggested to recalibrate the probes, vary the voltage with smaller increments and perform the measurements by varying the voltage from +5 V to -5 V and then back to +5 V again and also varying the frequency from 10 KHz to 1.2 MHz. Index Terms — Capacitance-voltage curve, Capacitancefrequency curve, Flat band voltage, MOS Capacitor, VEE Pro, VLSI