Remote Plasma Silicon Carbide Deposition for Conformal Low-Leakage Films
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Solution Overview
Problem
Current plasma-enhanced chemical vapor deposition (PECVD) processes face challenges in depositing high-quality silicon carbide thin films with excellent step coverage, low dielectric constants, high breakdown voltages, low leakage currents, and porosity, while avoiding oxidation of exposed metal surfaces.
Innovation Solution
A method involving the deposition of silicon carbide films using a remote plasma source, where silicon-containing precursors with Si—H bonds and hydrocarbon co-reactants are used, generating hydrogen radicals in a ground state to react with the precursors and form doped or undoped silicon carbide films without C—C, C—O, or C—N bonds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma-enhanced chemical vapor deposition (PECVD) is used to deposit silicon carbide thin films, then the films can achieve high conformality and good step coverage, but the process may cause oxidation of exposed metal surfaces and produce unwanted C—C, C—O, or C—N bonds in the film
Solution Approach 1:
The patent changes the plasma generation location from near the substrate to a remote location upstream, and changes the radical state from excited to ground state. This allows the use of silicon-containing precursors with Si—H bonds that react selectively to form Si—C bonds without forming unwanted C—C, C—O, or C—N bonds, while maintaining high conformality and step coverage
Solution Approach 2:
The patent introduces ground state hydrogen radicals as an intermediary species that mediates the reaction between silicon-containing precursors and the substrate. These ground state radicals enable selective Si—H bond activation and Si—C bond formation without causing oxidation or forming unwanted carbon-containing bonds
2Productivity
If conventional PECVD processes are used, then deposition can occur at reasonable rates, but the films exhibit high leakage currents and low breakdown voltages
Solution Approach 1:
The patent changes the energy state parameter of hydrogen radicals from excited to ground state by generating them in a remote plasma source upstream from the substrate. This parameter change results in films with significantly improved electrical properties including lower leakage currents and higher breakdown voltages, while maintaining acceptable deposition rates
Solution Approach 2:
The patent segments the deposition process into two distinct zones: a remote plasma generation zone upstream where radicals are created, and a deposition zone at the substrate where ground state radicals react with precursors. This segmentation allows control over radical energy state and reaction selectivity, improving film quality and electrical properties
3Productivity
If excited state hydrogen radicals are used in PECVD, then deposition reactions proceed rapidly, but the films contain unwanted C—C, C—O, and C—N bonds
Solution Approach 1:
The patent performs preliminary action by generating hydrogen radicals in a remote plasma source upstream from the substrate, allowing them to relax to ground state before reaching the deposition zone. This preliminary relaxation ensures that only desired Si—C bonds are formed without unwanted C—C, C—O, or C—N bonds in the final film
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 method achieves high conformality, preserves Si—C, Si—O, and Si—N bonds, and results in films with improved electrical properties, such as high breakdown voltages and low leakage currents, while maintaining low dielectric constants and porosity.
Implementation Method 1
generating, from a hydrogen source gas, radicals of hydrogen in a remote plasma source
Implementation Method 2
A method of depositing a silicon carbide film on a substrate... flowing a silicon-containing precursor into the reaction chamber... flowing a co-reactant into the reaction chamber
Data Source
AI summary
A doped or undoped silicon carbide film can be deposited using a remote plasma chemical vapor deposition (CVD) technique. One or more silicon-containing precursors are provided to a reaction chamber. Radical species, such as hydrogen radical species, are provided in a substantially low energy state or ground state and interact with the one or more silicon-containing precursors to deposit the silicon carbide film. A co-reactant may be flowed with the one or more silicon-containing precursors, where the co-reactant is a carbon-containing precursor and each silicon-containing precursor is a silane-based precursor with at least a silicon atom having two or more hydrogen atoms bonded to the silicon atom.