Gate Oxide Leakage and Floating Gate Capacitor Matching Test

Abstract

Capacitor matching is an important device parameter for precision analog applications. In the last ten years, the floating gate measurement technique has been widely used for its characterization. As technologies advance, however, new challenges emerge. In this paper we describe the impact of MOSFET thin gate oxide leakage on the technique. SPICE simulation, bench measurement, analytical model and numerical analyses are presented to illustrate the problem and key contributing factors. In addition, we propose a field MOSFET approach to solve the problem. Since field oxide thickness is typically several thousand Angstroms, gate leakage is negligible. Thick gate oxide MOSFET and Field MOSFET measurement data are compared.