Vanadium Nitride Gate Layers for Surface Depletion and Work Function
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Solution Overview
Problem
Conventional gate electrode materials in CMOS devices, such as doped polysilicon, face challenges with surface depletion and non-ideal effective work function, particularly in advanced node applications, necessitating the search for alternative materials with higher work function values.
Innovation Solution
The formation of vanadium nitride-containing layers using a thermal cyclical deposition process, involving the sequential introduction of vanadium and nitrogen precursors, which can be used as a work function metal in gate electrodes, offering improved selectivity and properties for advanced node applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If doped polysilicon is used as gate electrode material, then the device can be manufactured with conventional processes, but the gate electrode exhibits surface depletion and non-ideal effective work function in advanced node applications
Solution Approach 1:
The patent changes the material composition parameter by introducing vanadium nitride (VN) as a gate electrode material or liner layer, replacing conventional doped polysilicon. This material substitution fundamentally alters the work function characteristics and eliminates surface depletion effects, thereby improving gate electrode performance for advanced node applications while maintaining compatibility with existing manufacturing processes
Solution Approach 2:
The patent employs composite material structures where vanadium nitride is integrated with other materials such as titanium nitride (TiN) or used as a liner layer within multi-layer gate electrode configurations. This composite approach combines the high work function and low depletion characteristics of VN with the beneficial properties of companion materials to achieve optimal device performance
2Reliability
If titanium nitride layer is used to replace polysilicon, then the effective work function is improved, but higher work function values are still desired for PMOS regions and certain applications
Solution Approach 1:
The patent utilizes parameter changes by controlling the composition, thickness, and deposition conditions of vanadium nitride layers to achieve a wide range of work function values. By adjusting the VN content and layer structure, the patent can tailor the effective work function to meet different requirements for NMOS, PMOS, and other specialized applications, providing greater adaptability than titanium nitride alone
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The vanadium nitride-containing layers provide high work function values, enabling improved performance and selectivity, addressing the limitations of traditional gate electrode materials by enhancing the effective work function and reducing surface depletion effects.
Implementation Method 1
depositing a vanadium nitride-containing layer onto a surface of the substrate, wherein the deposition process comprises: providing a vanadium precursor to a reaction chamber and providing a nitrogen precursor to the reaction chamber
Data Source
AI summary
Methods of forming a vanadium nitride-containing layer comprise providing a substrate within a reaction chamber of a reactor and depositing a vanadium nitride-containing layer onto a surface of the substrate, wherein the deposition process comprises providing a vanadium precursor to the reaction chamber and providing a nitrogen precursor to the reaction chamber.