Stress-induced capacitance approximation using ring oscillator delay

Abstract

This study proposes an approach to estimate parasitic capacitance shift under mechanical stress. The silicon-on-insulator n-/p- metal-oxide-semiconductor field-effect transistors (MOSFETs) and CMOS ring oscillators (ROs) were fabricated side by side in this study. External compressive stresses were applied on a <110> strained channel of n-/p-MOSFETs and ROs in longitudinal and transverse configurations. The modeling mobilities of CMOS ROs used the measurement results of n-/p-MOSFET to simulate their oscillation frequencies under external stresses. The frequency difference between the experiment and simulation indicates parasitic capacitance variation under stresses.