Semiconductor device

Abstract

A semiconductor device 100 comprising: gate electrodes 126 arranged inside trenches 122 and facing p-type base regions 116, via gate insulating films 124, in a side wall section; shield electrodes 130 arranged inside the trenches 122 and positioned between the gate electrodes 126 and the bottom of the trenches 122; electrical insulation regions 128 inside the trenches 122, spreading between the gate electrodes 126 and the shield electrodes 130 and spreading along the side wall and bottom of the trenches 122 and isolating the shield electrodes 130 from the side walls and bottom; and a source electrode 134 electrically connected to n+ source regions 118 and the shield electrodes 130. The shield electrodes 130 have a high-resistance region 130a positioned on an n+ drain region 112 side and a low-resistance region 130 positioned on the gate electrode 126 side. As a result, ringing and surge voltage can be suppressed, malfunctions can be suppressed, and increase in switching loss can be prevented.

Description

technical field [0001] The present invention relates to semiconductor devices. Background technique [0002] Conventionally, a semiconductor device having a structure called a gate shield (Shield Gate) has been widely known (for example, refer to Patent Document 1). As shown in FIG. 20(a), a conventional semiconductor device 900 includes: a semiconductor base 910 including: an n+ type drain region 912, an n-type drift region 914, a p-type base region 916, and an n+ type source region 918 Trench (Trench) 922, has: be formed in semiconductor substrate 910, and the trench bottom adjacent to n-type drift region 914, and adjacent to p-type base region 916 and n-type drift region 914 connected sidewall, and formed in a stripe (Stripe) shape from a plan view; the gate electrode 926 is arranged in the trench 922, and is opposed to the p-type base region 916 via the insulating film 924 at the sidewall portion; The shielding electrode 930 is arranged in the trench 922 and is located...

AI Technical Summary

Problems solved by technology

[0007] However, once a high-resistance shield electrode is used as the shield electrode as described above, in the second half of the switching cycle, since a potential difference occurs along the wiring of the shield electrode, the gate-source capacitance C GS (Refer to Figure 20, it is the same situation in Figure 2) Gate voltage V GS It will rise suddenly, so there is a problem of easy operation error (self-turn-on (Self Turn-On)) (refer to symbol A in Figure 2(b))

In addition, due to the slow switching speed (see Figure 2(b)), there is also the problem of increased switching loss

[0008] On the other hand, if a low-resistance shield electrode is used as the shield electrode (see Fig. 3(a)), since the potential change of the drain electrode cannot be moderated when the switch is turned off, it is impossible to obtain ringing suppression at the same time. Effect of reducing surge voltage (see Figure 3(b))

Images