Utilization of Poly Heater Test Structures in the Characterization of Bias Temperature Instability

Test structures with a poly heater and a dedicated diode were employed in the characterization of bias temperature instability for 5V MOS devices in a 0.18μm CMOS smart power technology. Utilization of poly heater provides in situ temperature changes to allow different temperatures for stress and measurement and produces BTI degradation results with reduced relaxation in measurement, in good agreement with data from fast measurement system. Methodology for feedback temperature control was established and can be applied to different shapes and geometries of poly heater test structures. The test approach of utilizing poly heater for NBTI characterization provides a tool for fast NBTI assessment of wafer level reliability.