*3.3. Impact of Interface Traps*

The impact of the interface traps was investigated by resorting to the following strategy. The traps were virtually removed by (i) reducing *VTH*(*T*0) to 4 V, (ii) decreasing *aVTH* to 2 mK−1, (iii) multiplying the current factor *K*(*T*0) by 50 to annihilate the degradation of mobility μ*n*(*T*0), and (iv) setting *cm* = 0 to eliminate the influence of Coulomb scattering on μ*<sup>n</sup>*, which will thus exhibit a negative temperature coefficient over the whole temperature range. Figure 7 shows the comparison between the *real* 4H-SiC DUT and the *ideal* traps-free counterpart in terms of transfer characteristics at *VDS* = 20 V and various *TB* values. It can be inferred that:


To further corroborate the above findings, Figure 8 reports the temperature coefficient of the drain current *ID*, given by [19,20,25]

$$a\_T = \left. \frac{\partial I\_D}{\partial T} \right|\_{V\_{DS}} \tag{17}$$

for the real DUT and its traps-free variant at reference temperature *T*0 and drain-source voltage *VDS* = 20 V; it is again witnessed that the traps at the SiC/SiO2 interface lead to a detrimental highly-positive α*T* within a broad range of currents.

**Figure 7.** Modeled *ID*–*VGS* transfer characteristics at *VDS* = 20 V and *TB* = 303, 348, 423, and 473 K: comparison between the real DUT (blue lines) and the traps-free counterpart (magenta). ZTC stands for zero-temperature coefficient.

**Figure 8.** Temperature coefficient α*T* of the drain current at *TB* = *T*0 and *VDS* = 20 V for the real DUT (blue line) and its traps-free version (magenta).
