INSTRUMENTATION DESIGN FOR CROSS-CORRELATION MEASUREMENTS BETWEEN GATE AND DRAIN LOW FREQUENCY NOISE IN MOSFETS

摘要

A two-channel measurement system suited for the on-wafer characterization of the gate and drain low frequency noise in MOSFETs is presented. Guidelines for designing the preamplifier and the bias stage at the drain and gate terminals are discussed. Results show that, the natural choice of employing transimpedance amplifiers as first preamplifier stage is useful only at the gate side, while it is preferable the use of voltage preamplifiers at the drain side to avoid voltage saturation. A simple prototype which implements the proposed design approach is reported. The system capability is tested through the measurement of the gate noise, the drain noise and the cross-correlation between the two channels in nMOSFETs with ultrathin oxide thickness.