研究目的
To efficiently evaluate the reliability of an RF semiconductor device when several different mechanisms contribute simultaneously to its wearout, specifically for GaN HEMT devices.
研究成果
The developed process for quantifying the individual degradation mechanisms for wearout in solid state RF devices and determining the corresponding mean times to failure in an actual RF application is economical, quick, and allows clearer identification of signature parameters with the mechanisms compared to conducting the entire study with RF lifetests.
研究不足
The technique requires that each signature parameter measures the extent of one mechanism and is not affected significantly by the others, and that the mechanisms remain the same under DC and RF stress. The amount of degradation must be small, and equal and constant degrees of RF gain compression must be applied in all the tests.
1：Experimental Design and Method Selection:
The technique involves finding DC parameters that are 'signatures' of each degradation mechanism, performing separate DC-stress lifetests to find the degradation rates for the signature parameters at several temperatures, and the corresponding Arrhenius curves. An RF-stress lifetest is then performed to determine the 'scaling factors' between the rates of change in the DC lifetests and the rates of change in the RF application.
2：Sample Selection and Data Sources:
Discrete transistors were used for DC lifetests, and 1-stage 62 GHz MMIC amplifiers containing the same transistor were used for the RF lifetests.
3：List of Experimental Equipment and Materials:
Standard quiescent operating bias is Vd = 12 V, Id = 276 mA/mm. Parts were kept dark in closed fixtures, with flowing dry nitrogen.
4：Experimental Procedures and Operational Workflow:
DC and RF lifetests were stopped at appropriate intervals, the stress was turned off, and the base temperature (Tb) set to 50 °C, for characterizations. DC characterizations were conducted with slow (ms) pulsing, and consisted of a full suite of approximately 20 parameters.
5：Data Analysis Methods:
Changes in signature parameters were plotted versus time, and the data were fitted to find mean times to failure and construct Arrhenius plots to find thermal activation energies.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
