Tungsten silicide nitride films and methods of formation

Abstract

Embodiments of the present invention include tungsten silicide nitride films and methods for depositing tungsten silicide nitride films. In some embodiments, a thin film microelectronic device includes a semiconductor substrate having a tungsten gate electrode stack comprising a tungsten silicide nitride film having a formula WxSiyNz, wherein x is about 19 to about 22 atomic percent, y is about 57to about 61 atomic percent, and z is about 15 to about 20 atomic percent. In some embodiments, a method of processing a substrate disposed in physical vapor deposition (PVD) chamber, includes: exposing a substrate having a gate insulating layer to a plasma formed from a first process gas comprising nitrogen and argon; sputtering silicon and tungsten material from a target disposed within a processing volume of the PVD chamber; depositing atop the gate insulating layer a tungsten silicide nitride layer as described above; and depositing a bulk tungsten layer atop the tungsten silicide nitridelayer.

Description

technical field [0001] Embodiments of the present disclosure relate generally to substrate processing systems and methods, and, more particularly, to tungsten nitride suicide films and methods of depositing tungsten nitride suicide films. Background technique [0002] Tungsten (W) is frequently used as a gate conductor material in the fabrication of integrated circuits including dynamic random access memory (DRAM). However, integrating tungsten into semiconductor processing involves several significant challenges. For example, the fabrication of a typical tungsten gate electrode stack involves forming a gate oxide layer on a silicon substrate, eg, by thermal oxidation or chemical vapor deposition (CVD). Subsequent deposited bulk tungsten films have relatively poor adhesion to the gate oxide layer. Therefore, prior to the deposition of the bulk tungsten film, an adhesion layer (ie glue layer), such as tungsten silicide (WSi) or tungsten nitride (WN), is deposited on the gat...

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Problems solved by technology

However, the inventors have observed that the adhesion layer often exhibits unsatisfactory adhesion to the underlying oxide and subsequently deposited bulk tungsten, and also fails to provide suitable resistivity for the gate stack.

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