HVMOS reliability evaluation using bulk resistances as indices

摘要

A method of determining the reliability of a high-voltage PMOS (HVPMOS) device includes determining a bulk resistance of the HVPMOS device, and evaluating the reliability of the HVPMOS device based on the bulk resistance.

主权项

1. A method comprising:
determining a bulk resistance of a high-voltage PMOS (HVPMOS) device, wherein the determining the bulk resistance comprises:
measuring a plurality of source-to-bulk voltages of the HVPMOS device using a tester;measuring a plurality of source currents of the HVPMOS device corresponding to the plurality of source-to-bulk voltages;calculating a plurality of candidate bulk resistances from the plurality of source-to-bulk voltages and the plurality of source currents; andselecting the bulk resistance from the plurality of candidate bulk resistances, with the bulk resistance being calculated from a source-to-bulk voltage in a pre-determined range, with the source-to-bulk voltage being one of the plurality of source-to-bulk voltages; determining a reference bulk resistance comprising:
forming a plurality of reference sample HVPMOS devices;determining bulk resistances of the plurality of reference sample HVPMOS devices; andmeasuring current gains β of the reference sample HVPMOS devices, wherein the reference bulk resistance is determined as a bulk resistance of one of the reference sample HVPMOS devices having a current gain β equal to 1; and comparing the bulk resistance with the reference bulk resistance, wherein the HVPMOS device with the bulk resistance greater than the reference bulk resistance is determined as not reliable, and the HVPMOS device with the bulk resistance smaller than the reference bulk resistance is determined as reliable.