The Impact of Repetitive Unclamped Inductive Switching on the Electrical Parameters of Low-Voltage Trench Power nMOSFETs

Modeling the Impact of the Trench Depth on the Gate–Drain Capacitance in Power MOSFETs

“…Trench MOSFETs with TBOs have been manufactured with different trench depths so as to investigate the dependence of the C GD on the trench depth and validate the C GD model in (5). The fabrication process of the MOSFETs is detailed elsewhere [5].…”

“…The fabrication process of the MOSFETs is detailed elsewhere [5]. The gate voltage vs. charge characteristic is measured and is shown in Fig.…”

“…5 shows the importance of (3) since an increase in the trench depth (which is an increase in t D / for the same p-body) results in a decrease in the average oxide thickness overlapping the drain for TBO MOSFETs. The model in (5) was only able to predict the behavior of the experimental measurements when the effect of the sidewall capacitance was taken into account. Hence, the C GD characteristics in Fig.…”

“…Fig. 2 shows a series of normalized C GD curves generated using the model in (5) with N D = 1 x 10 16 cm -3 . The capacitances have been normalized by using capacitance at 1.3 µm trench depth as the reference.…”

“…These characteristics have been generated without taking the dependence of C GOX on the trench depth into account i.e. a constant value of C GOX is used in (5). Next, the dependence of C GOX on the trench depth is taken into account by using (3) and (5) to generate C GD vs. V D characteristics for different trench depths.…”