JP2017126636A

JP2017126636A - Semiconductor device

Info

Publication number: JP2017126636A
Application number: JP2016004298A
Authority: JP
Inventors: 太郎近藤; Taro Kondo; 俊介福永; Shunsuke Fukunaga
Original assignee: Sanken Electric Co Ltd
Current assignee: Sanken Electric Co Ltd
Priority date: 2016-01-13
Filing date: 2016-01-13
Publication date: 2017-07-20

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device that has a high switching speed and has a structure less likely to be damaged by discharging.SOLUTION: A semiconductor device has a structure having trench gate electrodes opposed to a semiconductor layer on a lateral face in a trench, and having a trench source electrode between the trench gate electrodes. A shape of bottom corners of the trench gate electrodes at a side opposed to the semiconductor layer is rounded. Further, when a distance between an upper corner of the trench gate electrode and an upper corner of the opposed trench source electrode is defined as a, and a distance between the bottom corner of the trench gate electrode and the trench source electrode opposed to the same is defined as b, a relation of a≥b is satisfied.SELECTED DRAWING: Figure 3

Description

本発明はスイッチング速度が速く、かつ、放電によって破壊しにくい構造の半導体装置に関する。 The present invention relates to a semiconductor device having a structure that has a high switching speed and is difficult to be destroyed by electric discharge.

容量を低減し、スイッチングスピードの速い半導体装置を実現する構造として、トレンチ内部電極を、トレンチゲート電極と、トレンチソース電極に分離させたトレンチゲート型構造が知られている。
2. Description of the Related Art A trench gate structure in which a trench internal electrode is separated into a trench gate electrode and a trench source electrode is known as a structure for realizing a semiconductor device with reduced capacitance and high switching speed.

特開２０１３−６９８５２号公報JP 2013-69852 A

しかしながら、本構造においては、ゲート電極と、ゲート電極と対向する半導体領域間で放電が生じやすく、電圧印加時に放電によって素子が破壊し易いという問題がある。本発明は、上記問題点を解決し、速いスイッチングスピード有し、放電によって素子の破壊の生じにくい半導体装置を提案することを目的とする。 However, in this structure, there is a problem that discharge is likely to occur between the gate electrode and the semiconductor region facing the gate electrode, and the device is easily destroyed by discharge when a voltage is applied. An object of the present invention is to propose a semiconductor device that solves the above-described problems, has a high switching speed, and is less likely to cause element breakdown due to discharge.

トレンチゲート型半導体において、トレンチ側面の半導体層と対向する側のゲート電極の下部角部の形状をラウンド形状にし、トレンチゲート電極上部角部と、これと対向するトレンチソース電極上部角部の距離をa, トレンチゲート電極底部角部と、これと対向するトレンチソース電極との距離をｂとした場合、a ＞ bの関係にする。
In the trench gate type semiconductor, the shape of the lower corner portion of the gate electrode on the side facing the semiconductor layer on the side surface of the trench is rounded, and the distance between the upper corner portion of the trench gate electrode and the upper corner portion of the trench source electrode facing this is set. a, where b is the distance between the bottom corner of the trench gate electrode and the opposite trench source electrode, a> b.

本発明によれば、スイッチングスピードが速く、放電によって素子の破壊の生じにくい、ＭＯＳを製造できる。 According to the present invention, it is possible to manufacture a MOS that has a high switching speed and is less likely to be damaged by a discharge.

従来技術のトレンチゲート型ＭＯＳの全体構造である。It is the whole structure of a conventional trench gate type MOS. 従来技術のトレンチゲート型ＭＯＳのトレンチ内部構造である。2 is a trench internal structure of a conventional trench gate type MOS. 本発明におけるトレンチゲート型ＭＯＳのトレンチ内部構造である。It is the trench internal structure of the trench gate type MOS in this invention.

以下、本発明の実施の形態となる構造について説明する。 Hereinafter, the structure which becomes embodiment of this invention is demonstrated.

実施例１に係るトレンチ内部の構造について説明する。実施例では、半導体装置の構造の一例としてＭＯＳを示している。図１は従来技術のトレンチゲート型ＭＯＳの全体構造、図２は従来型のトレンチゲート型ＭＯＳのトレンチ内部構造、図3は本発明の実施例１におけるトレンチゲート型ＭＯＳのトレンチ内部構造である。従来型のトレンチゲート電極構造と比較して、発明構造では、トレンチ側面の半導体層と対向する側のトレンチゲート電極の底部角部の形状がラウンド形状になっている。これによって、ゲートをＯＮした際の、ゲート電極とゲート電極と対向する半導体層での放電を避けることができる。また、半導体層と対向する側のトレンチゲート電極底部角部をラウンド化するだけでなく、その他のトレンチ電極角部をラウンド形状にしても、同様の効果が得られる。
さらに、前記トレンチゲート電極の上部角部と、対向する前記トレンチソース電極の上部角部間の距離をa, 前記トレンチゲート電極の下部角部と対向するトレンチソース電極下部角部の距離をｂとした場合、a ＞ bの関係とすることでトレンチゲート電極底部角部と対向する半導体領域の距離が長くなり、より効果的にトレンチゲート電極と、これと対向する半導体領域の放電を避けることができる。
The structure inside the trench according to the first embodiment will be described. In the embodiment, a MOS is shown as an example of the structure of the semiconductor device. FIG. 1 shows the overall structure of a conventional trench gate type MOS, FIG. 2 shows the trench internal structure of the conventional trench gate type MOS, and FIG. 3 shows the trench internal structure of the trench gate type MOS according to the first embodiment of the present invention. Compared with the conventional trench gate electrode structure, in the inventive structure, the shape of the bottom corner of the trench gate electrode on the side facing the semiconductor layer on the side surface of the trench is round. Thereby, it is possible to avoid discharge in the gate electrode and the semiconductor layer facing the gate electrode when the gate is turned on. In addition to rounding the bottom corner of the trench gate electrode on the side facing the semiconductor layer, the same effect can be obtained by rounding the other corner of the trench electrode.
Further, the distance between the upper corner of the trench gate electrode and the upper corner of the opposing trench source electrode is a, and the distance between the lower corner of the trench gate electrode facing the lower corner is b. In this case, the relationship of a> b increases the distance between the semiconductor region facing the bottom corner of the trench gate electrode, and more effectively avoids the discharge between the trench gate electrode and the semiconductor region facing this. it can.

１ソース電極、
２、トレンチソース電極
３、Ｎ＋ソース層
４、絶縁膜
５、Ｐ＋層
６、Ｎ−エピタキシャル層
７、トレンチゲート電極
８、Ｎ＋半導体基板
９、ドレイン電極
１０、トレンチ
１１、トレンチゲート電極底部角部 1 source electrode,
2, trench source electrode 3, N + source layer 4, insulating film 5, P + layer 6, N-epitaxial layer 7, trench gate electrode 8, N + semiconductor substrate 9, drain electrode 10, trench 11, trench gate electrode bottom corner

Claims

In a semiconductor device having a trench gate electrode facing a side semiconductor layer inside a trench and having a trench source electrode between the trench gate electrodes, a bottom corner of the trench gate electrode on the side facing the semiconductor layer The semiconductor device is characterized by a round shape.

The distance between the upper corner of the trench gate electrode and the upper corner of the trench source electrode facing it is a, and the distance between the bottom corner of the trench gate electrode and the trench source electrode facing it is b. 2. The semiconductor device according to claim 1, wherein a> b is satisfied.