Cyclical Deposition Micro Pulsing for Uniform Metal Carbide Films
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Solution Overview
Problem
Conventional doped polysilicon gate electrodes in CMOS technology face challenges such as gate depletion and non-ideal effective work function, especially in advanced technology nodes, and struggle with conformal deposition on high aspect ratio device features, leading to non-uniform material films.
Innovation Solution
A cyclical deposition process involving micro pulsing of vapor phase reactants, such as atomic layer deposition, is used to deposit transition metal aluminum carbide films, ensuring a consistent concentration of reactants and achieving conformal, uniform deposition on substrates, including high aspect ratio features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If doped polysilicon is used as gate electrode material, then the gate electrode is conductive, but gate depletion occurs creating an extra gate insulator thickness
Solution Approach 1:
The patent changes the material parameter from doped polysilicon to metal carbide (such as titanium carbide, tungsten carbide, or molybdenum carbide), which fundamentally alters the electrical and physical properties to eliminate gate depletion while maintaining conductivity and achieving ideal effective work function for both NMOS and PMOS devices
2Productivity
If conventional deposition methods are used on high aspect ratio features, then deposition speed is maintained, but conformal uniformity is poor
Solution Approach 1:
The patent employs atomic layer deposition (ALD) which uses periodic, cyclic deposition steps with precise timing control. Each cycle involves sequential exposure to precursor and co-reactor gases in controlled pulses, ensuring uniform conformal coating even on high aspect ratio structures while maintaining efficient deposition rates
Solution Approach 2:
The patent replaces conventional physical vapor deposition or chemical vapor deposition methods with atomic layer deposition, which uses precisely controlled chemical reactions in the vapor phase. This substitution enables atomic-level precision in film thickness control and superior conformality on complex three-dimensional 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 method provides a more ideal effective work function for both NMOS and PMOS devices and ensures uniform, high-quality material films with reduced thickness non-uniformities, improving the performance of semiconductor devices.
Implementation Method 1
contacting the substrate with a first vapor phase reactant; contacting the substrate with a second vapor phase reactant by two or more micro pulsing processes
Data Source
AI summary
A method of depositing a material film on a substrate within a reaction chamber by a cyclical deposition process is disclosed. The method may include: contacting the substrate with a first vapor phase reactant and purging the reaction chamber with a first main purge. The method also includes: contacting the substrate with a second vapor phase reactant by two or more micro pulsing processes, wherein each micro pulsing process comprises: contacting the substrate with a micro pulse of a second vapor phase reactant; and purging the reaction chamber with a micro purge, wherein each of the micro pulses of the second vapor phase reactant provides a substantially constant concentration of the second vapor phase reactant into the reaction chamber. The method may also include; purging the reaction chamber with a second main purge. Device structures including a material film deposited by the methods of the disclosure are also disclosed.