Electrothermal Simulation of Self-Heating in DMOS Transistors up to Thermal Runaway

Experimental Reliability Improvement of Power Devices Operated Under Fast Thermal Cycling

“…Metal migration starts in the regions of maximum temperature gradients and accumulates and generates peak mechanical stress in the regions of maximum temperature [3]. This applies to our case as shown in Fig.2.a, which depicts a typical 2-D temperature distribution simulated with the electro-thermal simulator presented in [7]. It can be observed that the highest temperature gradients (represented by black arrows) are at the edges of the device, and are pointing towards the center of the device.…”

Physics-based stability analysis of MOS transistors

“…This current I c is in turn multiplied by avalanche when flowing in the drift extension, resulting in a positive feedback behavior. Self-heating [5,8,16] is included in the model by introducing an effective thermal impedance Z th;eff % ðT j À T amb Þ=P d [6], where it is assumed for simplicity that the dissipated power P d is independent of the pulse time t pulse .…”

“…The temperature coefficient of I dMOS depends on V gs [17], I ii has a slightly-negative temperature coefficient [18] (not included in the model), and I c has a positive temperature coefficient [19]. In most cases, the increase in I c (also including thermal leakage) induced by self-heating determines thermal instability [2,3,5,8]. However, for V gs below the zero-temperature coefficient point, I dMOS also contributes to instability [5,8,17].…”

“…In order to overcome the first drawback, physics-based models [2,3,5,7,8] or TCAD simulations [9] have been used to predict and quantify instability. However, modeling and simulating runaway effects causes the output parameters to diverge and makes it difficult to identify the physical origin of the numerical instability.…”

“…For this purpose analytical models for MOS transistors, TCAD simulations, experimental data or combinations can be used [2,3,5,[7][8][9]13]. In this work, physics-based analytical expressions [14,15] with experimental [6] fitting parameters have been used (Appendix A).…”