Turn-on Switching Energy Research Articles

Comprehensive Analysis of Electrical Parameters Degradations for SiC Power MOSFETs Under Repetitive Short-Circuit Stress

The degradations of electrical parameters for silicon carbide power MOSFETs under repetitive short-circuit (SC) stress are investigated in detail in this paper. It demonstrates that the generation of negative charges along the gate–oxide interface of the channel region is the dominant degradation mechanism, which results in the increase in the threshold voltage ( ${V}_{\text {th}}$ ) and the rise of ON-state resistance ( ${R}_{\text {dson}}$ ) under low gate voltage bias condition. Furthermore, degradations of dynamic characteristics including gate charge ( ${Q}_{\text {g}}$ ) and switching behaviors of the device after the repetitive SC stress are extracted and analyzed for the first time. It illustrates that the increased ${V}_{\text {th}}$ contributes to the rise of the Miller plateau voltage ( ${V}_{\text {gp}}$ ), which further leads to the increase in gate–source charge ( ${Q}_{\text {gs}}$ ). Meanwhile, the increase in the turn-ON time and the reduction of turn-OFF time are observed, which are also resulted from the positive shifts of ${V}_{\text {th}}$ and ${V}_{\text {gp}}$ , leading to the rise of turn-ON switching energy ( ${E}_{{ \text {on}}}$ ) and the decline of turn-OFF switching energy ( ${E}_{\text {off}}$ ), respectively.

Experimental study on the influence of junction temperature on the relationship between IGBT switching energy loss and device current

Accurate determination of power losses in semiconductor devices is important for optimal design and reliable operation of a power converter. The switching loss is an important component of the total device loss in an insulated-gate bipolar transistor (IGBT) in a voltage source inverter. The objective here is to study experimentally the influence of junction temperature on the turn-on switching energy loss Eon and turn-off switching energy loss Eoff. More specifically Eon and Eoff are both related to device current Ic; the influence of junction temperature on the relationship between Eon and Ic and that between Eoff and Ic is studied. As the operating environmental conditions and load conditions of power converter vary widely, a wide range of junction temperatures between −35°C and +125°C is considered here. The experimental data enable precise determination of the switching loss in each device in a high-power converter at any practical operating condition. This leads to precise estimation of total device loss and optimal thermal design of the converter. This further helps off-line and/or on-line estimation of device junction temperatures required for study of thermal cycles and reliability.

Experimental and comparative study of gamma radiation effects on Si-IGBT and SiC-JFET

This paper deals with an experimental study and a comparative study of the effects of total ionising dose of 60Co gamma radiation on Si-IGBT and SiC-JFET. The response of the threshold voltage and the turn-on switching parameters are reported for both devices. Charge trapping in the gate oxide causes the decrease of the threshold voltage for Si-IGBT. The decrease of this parameter combined with the behaviour of Miller plateau during irradiation results in a decrease of the collector current rise-time, the collector-emitter voltage fall-time, and the turn-on switching energy and in an increase of the peak of the turn-on switching power and of the turn-on overshoot collector current. No changes in these parameters are observed for SiC-JFETs up to 2900Gy with a dose rate of 2.80Gy/h. This indicates that those SiC-JFETs have extremely high radiation resistance with respect to the TID effects compared to the Si-IGBTs.

Total ionising dose effects on punch-through insulated gate bipolar transistors turn-on switching behaviour

This paper deals with the effects of 60Co gamma irradiation on punch-through commercial insulated gate bipolar transistor turn-on switching behaviour. The response of the threshold voltage and the turn-on switching parameters under three different in situ gate biases are described. Charge trapping in the gate oxide causes the decrease of the threshold voltage. It is shown that the decrease of this parameter and the decrease of the Miller plateau level result in a decrease of the collector current rise-time, the collector–emitter voltage fall-time, the turn-on switching energy and in an increase of the peak of the turn-on switching instantaneous power and of the turn-on overshoot collector current.

A 500V, Very High Current Gain (β=1517) 4H-SiC Bipolar Darlington Transistor

A 500V, Very High Current Gain (β=1517) 4H-SiC Bipolar Darlington Transistor