Electrical parameters degradation of power RF LDMOS device after accelerated ageing tests

This paper reports novel methods for accelerated ageing tests, with comparative reliability between them for stresses applied on power RF LDMOS: Thermal Shock Tests (TST), Thermal Cycling Tests (TCT), High Voltage Drain (HVD) and coupling thermal and electrical effects under various conditions. The investigation findings obtained after various ageing tests show the degradation and the device’s performance shifts for most important electric parameters such as transconductance (Gm), on-state resistance (Rds_on), feedback capacitance (Crss) and gatedrain capacitance (Cgd). This means that the tracking of these parameters enables to consider the hot carrier injection as the dominant degradation phenomenon. However, this is explained by excitation and trapping of electrons in the oxide-silicon interface at the drain side. A physical simulation software (2D, Silvaco-Atlas) has been used to locate and confirm degradation phenomena.