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Wafer-level Accelerated Lifetesting of Individual Devices

The thermal activation energies of TriQuint Semiconductor's TQPED devices are evaluated with an innovative wafer-level technique for accelerated life testing. The method was used to determine the activation energy for. both the depletion-mode and enhancement-mode pHEMT devices. An on-wafer heating element around individual devices allowed stressing at various temperatures on the same wafer. Temperatures above 275degC were easily achieved without the need to self-heat the transistors. The technique allows for the separation of thermally activated mechanisms from any influence of bias. The wafer-level aspect of stressing provides a spatial map of reliability for a wafer. A single wafer provides adequate samples to evaluate lifetime distributions. Without the need for hundreds of devices and long-term life testing at lower temperatures, this method allows for a rapid and efficient evaluation of device reliability. By doing lifetime aging studies on wafer, packaging considerations are eliminated. The wafer form factor makes it easier to observe physical device degradation and subsequently perform root cause analysis of the failure mechanism.