Abstract
This study presents firstly, experimental results through an innovative reliability bench of pulsed RF life test in a radar application for device lifetime under pulse conditions, then the physical clarifications of the failure phenomenon. The results of accelerated aging stress relative to various temperatures (3000 h at 150 and 10°C) are presented. Based on the radio-frequency (RF) behaviour parameters shifts (gain, Pout, drain efficiency: DE, and Psat), the reliability of different tests have been compared. To explain and confirm these effects according to the degradation data, the dominant physical phonemes involved have been studied and the failure modes of the metal-oxide-semiconductor field-effect transistors have been examined and proved with the SILVACO-ATLAS simulator. What supports finding a relationship between the shifts of RF electrical parameters to failure physical phenomena caused by impact ionisation. The behaviour degradation of N-LDMOS is related to interface states generated by hot carriers (traps) and by the electrons that are trapped, which leads to an accumulation of negative charge at the Si/SiO2 interface. At low temperature, the interface states are created more, due to a maximum impact ionisation rate targeted in the gate edge area. Finally, RF behaviour reliability analysis has been discussed.