On-Chip In-Place Measurements of V_th and Signal/Substrate Response of Differential Pair Transistors

Abstract

In-place AC measurements of the signal gain and substrate sensitivity of differential pair transistors of an analog amplifier are combined with DC characterization of the threshold voltage (V_th) of the same transistors. An on-chip continuous time waveform monitoring technique enables in-place matrix measurements of differential pair transistors with a variety of channel sizes and geometry, allowing the wide coverage of experiments about the transistor-level physical layout dependency of substrate noise response. A prototype test structure uses a 90-nm CMOS technology and demonstrates the geometry-dependent variation of substrate sensitivity of transistors in operation.