Two Transistors Voltage-Measurement-Based Test Structure for Fast MOSFET Device Mismatch Characterization

Abstract

This work presents a test structure targeted to measure MOSFET mismatches with a fast method. It relies on two single-spot voltage measurements in order to extract $\Delta V_{TH}$ and $\Delta \beta / \beta $ separately. The new methodology gives a theoretical increase in the measurement speed of 30x (23.17x in practice). The coefficient of determination ( $R^{2}$ ) of the linear regression analysis is used to compare standalone transistor measurements against the new proposed methodology. The correlation in the data demonstrates values not less than 0.94 ( $R^{2}\geq0.94$ ). The test structure can reproduce parameter correlations, and it is capable of extracting MOSFET mismatch design parameters, such as Pelgrom’s $A_{V_{TH}}$ , with an error of 2% and $A_{\beta }$ , with a negligible error. The experimental data presented herein are taken from measurements in prototypes fabricated in a 65nm CMOS bulk process. The whole circuit is composed of 16 2D addressable DUT device matrices, each having 256 same-size closely-placed MOSFET devices, totaling 4,096 MOS devices used in single-type (NMOS) transistor array.