REMOTE PLASMA LOW TEMPERATURE SiN/SiC/SiCN FILM FORMATION
Publication Date: 2017-Jun-21
The IP.com Prior Art Database
REMOTE PLASMA LOW TEMPERATURE SIN / SIC / SICN FILM FORMATION
The deposition of SiN / SiCN / SiC films for widely application faces the following problem.
- Plasma damage reduction with remote plasma:
Deposition did not use direct plasma source but used remote plasma source. Thereby, it does not come in for the big plasma damage to the substrate.
- High quality (and stoichiometric) SiN/SiC/SiCN film with High deposition rate
- Low deposition temperature
è Deposition obtained even at room temperature using Si source with remote plasma regime. The invention can use for the many kinds of device/ substrate materials which are temperature sensitive.
The low-temperature deposition obtained silicon nitride / silicon carbide / silicon carbonitride films using by remote plasma CVD. The remote plasma CVD process differs from conventional and direct PECVD process in two ways: (a) only a subset of the process reactants and/or diluents are directly plasma excited; and (b) thin film deposition takes place on a substrate that is outside of the plasma glow region. In order to: (a) restrict the multiplicity of reaction pathways, (b) control film content stoichiometry; and (c) minimize hydrogen impurity incorporation, the Si source reactant is never directly plasma excited.
To improve film quality of deposited films using remote plasma, preferably, high dilution of Si-source with gas addition should be required. Higher flow rate of Si-source with carrier gas leads gaseous partial reaction with remote plasma reactant and the completion of the reaction on the substrate.
Moreover, low vapor pressure Si compound can easily change to non-volatile solid or liquid products at low temperature. These types of deposited products (solid / liquid) must be reacted completely on the substrate. Presence of many Si-H bonds in the original Si molecule helps to be reacted with plasma activated reactants
Reaction combinations are listed below:
1) SiN film formation: silylamine + N-reactant (Ex. from remote plasma N2 / NH3)
Such molecules are used for Si source:
- One of low vapor pressure polysilane or silyl amine of the general formula SixHyNz where x=3-5, z=1-2 and y=2x+z+2 or 2x+z, the molecule should be chain, branched or cyclic molecule without any N-N bond or Si-Si bonds.
- Most preferably, the molecule is trisilylamine, (SiH3)3N.
2) SiCN film formation: polysilaalkane + N-reactant (Ex. from remote plasma N2 / NH3)
Such molecules are used for Si source
- One of low vapor pressure polysilaalkane of the general formula SixCyHz, where z=2x+2y or 2x+2y+2, x=y or x>y, x+y must be included between 3 and 9, preferably 4 or 5, the molecule should be chain or branched molecule.
- Silyl-ligand (-SiH3) helps the reaction with N-reactant, Si molecule has at least one of –SiH3 terminated ligand
- The molecule does not have Si-Si bond in molecule
- Most preferably, the molecules are 1,3-disilabutane, 1,4-disilabutane, or 1,3,5-trisilapentane.