Semiconductor device

Abstract

A semiconductor device 100 is provided with: a gate electrode 126 disposed in a trench 122 with a portion at a side wall opposite to a p type base region 116 via a gate insulating film 124; a shield electrode 130 disposed in the trench 122 and positioned between the gate electrode 126 and the bottom of the trench 122; an electric insulation region 128 in the trench 122, which extends between the gate electrode 126 and the shield electrode 130, and furthermore, along the side wall and the bottom of the trench 122, and isolates the shield electrode 130 from the side wall and the bottom; and a source electrode 134, which is electrically connected to an n+ type source region 118, and is also electrically connected, at both end portions of the trench 122, to the shield electrode 130 in plan view. The shield electrode 130 has, in plan view, high-resistance regions 130a positioned at both the end portions of the trench 122, and a low-resistance region 130b positioned at a position sandwichedbetween the high-resistance regions 130a. In the semiconductor device, ringing and a surge voltage can be suppressed, a malfunction can be suppressed, an increase of a switching loss can be eliminated, and adverse effects due to a surge voltage from the outside can be reduced.

Description

Technical field [0001] The present invention relates to semiconductor devices. Background technique [0002] In the past, a semiconductor device having a so-called Shield Gate structure has been generally recognized (for example, refer to Patent Document 1). The conventional semiconductor device 900 such as Figure 23 As shown in (a), it includes: a semiconductor substrate 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; a trench (Trench) 922, It has a groove bottom formed in the semiconductor base 910 and adjacent to the n-type drift region 914, and sidewalls adjacent to the p-type base region 916 and the n-type drift region 914, and are viewed from the plane The gate electrode 926 is arranged in the trench 922 and faces the p-type base region 916 via the insulating film 924 at the sidewall part; the shield electrode 930 is arranged in the trench In the trench 922, and between the gate electr...

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 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 Figure 4 Symbol A in (b)

Also, due to the slow switching speed (refer to Figure 4 (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 Figure 5 as well as Image 6 (a)), since the potential change of the drain electrode cannot be moderated when the switch is turned off, the effect of suppressing the ringing and reducing the surge voltage cannot be obtained (see Image 6 (b))

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