HfMoN Gate Electrode Work Function Tuning
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Solution Overview
Problem
The existing CMOS technology requires complex and troublesome processes to form gate electrodes with different work functions, and there is a peeling issue between dielectric layers and electrodes due to material heterogeneity, necessitating a novel material to simplify the process and improve affinity.
Innovation Solution
A method involving the formation of a substrate with a first dielectric layer, followed by a metallic compound comprising hafnium, molybdenum, and nitrogen (HfMoN) which is doped and patterned to form a gate structure, along with a second dielectric layer, to create semiconductor devices and capacitors with improved homogeneity and reduced peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two layers of different metals are used to form gate electrodes with different work functions, then the threshold voltages of PMOS and NMOS can be adjusted to meet requirements, but the fabrication process becomes complex and troublesome requiring selective etching and multiple steps
Solution Approach 1:
The patent combines multiple metal elements (hafnium, molybdenum, nitrogen) into a single metallic compound layer (HfMoN) that can provide different work functions through compositional variation and doping, eliminating the need for separate metal layers and selective etching processes while maintaining the ability to adjust threshold voltages for both PMOS and NMOS transistors
Solution Approach 2:
The patent changes the compositional parameters of the metallic compound layer by varying the ratios of hafnium, molybdenum, and nitrogen, and by introducing dopants, to achieve different work functions within a single layer structure, thereby simplifying the fabrication process while maintaining adaptability for different transistor types
2Reliability
If high-k dielectric materials such as hafnium silicon oxynitride or titanium oxides are used to scale down capacitor size, then the dielectric constant increases, but material heterogeneity causes poor affinity between dielectric layer and electrode leading to peeling problems
Solution Approach 1:
The patent uses a composite metallic compound material (HfMoN) that combines multiple elements with complementary properties: hafnium provides high-k dielectric compatibility, molybdenum enhances mechanical strength and adhesion, and nitrogen improves chemical stability. This composite structure achieves both high dielectric constant and excellent affinity with dielectric layers, preventing peeling while maintaining manufacturability
Solution Approach 2:
The patent creates a homogeneous metallic compound layer where hafnium, molybdenum, and nitrogen are uniformly distributed at the atomic level, ensuring consistent material properties and strong interfacial bonding with dielectric layers, thereby eliminating the peeling issues caused by material heterogeneity in conventional multi-layer structures
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
This approach simplifies the formation of semiconductor devices with adjustable threshold voltages and enhances the affinity between dielectric layers and electrodes, reducing peeling issues and improving the scalability of semiconductor elements.
Implementation Method 1
a metallic compound is formed on the first dielectric layer, wherein the metallic compound comprises at least hafnium, molybdenum and nitrogen
Data Source
AI summary
A semiconductor device including a metallic compound Hfx1Moy1Nz1 as an electrode. The work function of the electrode can be modulated by doping the metallic compound with dopants including nitrogen, silicon or germanium. The metallic compound of the present invention is applicable to PMOS, NMOS, CMOS transistors and capacitors.