Formation mechanism of ultrathin WSiN barrier-layer in a W/WNx/Si system

被引：22

作者：

Nakajima, K ^{[1
]}

Akasaka, Y ^{[1
]}

Miyano, K ^{[1
]}

Takahashi, M ^{[1
]}

Suehiro, S ^{[1
]}

Suguro, K ^{[1
]}

机构：

[1] TOSHIBA CO LTD,ENVIRONM ENGN LAB,SAIWAI KU,KAWASAKI,KANAGAWA 210,JAPAN

来源：

APPLIED SURFACE SCIENCE | 1997年 / 117卷

关键词：

polymetal; tungsten; silicon; barrier metal; WSiN;

D O I：

10.1016/S0169-4332(97)80100-6

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

A W/WNx/poly-Si composite structure (poly-metal) has been proposed as a low resistivity gate material. It has been found that an ultrathin WSiN layer forms at the W/Si interface after annealing, and as a result. the W/WSiN/poly-Si structure is very stable up to 950 degrees C. Ln this paper, the formation mechanism of the ultrathin WSiN layer was studied. It was found that a 1 nm WSiN layer forms by solid state reaction between the WNx and poly-Si during annealing. A part of nitrogen atoms originally incorporated in the WNx film react with Si to form a 1 nm WSiN layer during annealing. Chemical bonds in the ultrathin WSiN layer consists of Si-N bonds and metallic W bonds. Metallic W bonds are attributed to W-W or W-Si bonds, There is no W-N bonds. Therefore, it is speculated that the WSiN consists of Si3N4 and W or WSix, and stabilizes the W/poly-Si interface, Since the WSiN layer acts as an excellent barrier metal for W and Si diffusion,the sheet resistivity of the poly-metal structure (where W thickness is 100 nm) can be maintained to be lower than 1.5 Ohm/sq.

引用

页码：312 / 316

页数：5

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