Chemical Vapor Deposition (CVD) is a process used to deposit thin films of a material onto a substrate by reacting gaseous precursors at a high temperature. In the case of MoS2, the process typically involves the thermal decomposition of a gaseous precursor such as molybdenum hexacarbonyl (Mo(CO)6) and hydrogen sulfide (H2S) on a substrate such as silicon or sapphire to form a thin film of MoS2. This technique can be used to produce high-quality, large-area MoS2 films for applications such as transistors, solar cells, and sensors.
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Researchers Using Chemical Vapor Deposition (CVD) of MoS2
A PHD Candiate from Michigan Tech University asks the following:
I need some conductive silicon wafer as substrate for CVD, and also I wish it can be etch resistant to KOH if possible. Do you have suggestions on the selection of your product?
I'm planning to use this wafer (150mm Silicon) for CVD growth of MoS2, and then use the as-grown sample to do electrochemical test. Therefore, I need the wafer to have good conductivity, even after exposure to ambient conditions.
Do you have some recommendations to my application?
UniversityWafer, Inc. recomended the following Si wafer options:
Silicon Wafers — 150 mm Examples
Dia
Type/Dop
Ori
Res (Ω·cm)
Thick
Polish
Comments
150 mm
N/As
(100)
0.001–0.005
675 μm
SSP
LTO Backside
150 mm
P/B
(100)
0.001–0.005
675 μm
DSP
1 Flat
150 mm
P/B
(100)
0.01–0.02
675 μm
SSP
1 Flat
150 mm
N/Sb
(100)
0.008–0.020
675 μm
SSP
1 Flat
150 mm
N/As
(111)
0.001–0.005
675 μm
SSP
1 Flat
If you are to use these for CVD deposition of MoS2, then do you expect to create monocrystalline MoS2? If so then perhaps crystallographic Ori of the substrates are significant to you and you should specify them.
Silicon is not resistant to KOH etch. In fact MEMS manufacturing consists of etching Silicon wafers in KOH. You can grow SiO2 layer on Silicon which will make it somewhat resistant to KOH. You can coat the wafers with Silicon Nitride and then it will be very resistant to KOH. We can sell any of above listed wafers coated with either SiO2 or Si3N4 films.
Electrical conductivity is a property of internal bulk material, so it is not affected by corrosion of the surface. On the other hand, if you are concerned with providing good electrical ohmic contact to the Silicon wafer and the MoS2 layer, then that is another matter. We can supply above wafers with Ohmic contact to a thin gold or copper or aluminium layer.
Please specify what you need and we will be please to quote a price.
The image above depicts the Chemical Vapor Deposition (CVD) process used to synthesize Molybdenum Disulfide (MoS₂) thin films, which is one of the most common methods for producing high-quality 2D materials.
The diagram shows:
CVD Furnace System:
A horizontal tube furnace with heating elements that can reach temperatures of 650-900°C
A quartz tube where the deposition takes place
SiO₂/Si substrate in the center where MoS₂ will grow
Two precursor boats containing:
MoO₃ (molybdenum oxide) - shown in purple
Sulfur - shown in yellow
Gas inlet for carrier gases (typically Argon/Hydrogen mixture)
Gas outlet connected to exhaust or vacuum pump
Chemical Process Visualization:
Vaporization of the precursors (MoO₃ and sulfur)
Transport of these vapors via carrier gas to the substrate
Surface reaction at the substrate forming MoS₂ crystalline structure
MoS₂ Atomic Structure (magnified view):
Hexagonal lattice arrangement
Molybdenum atoms (blue) sandwiched between two layers of sulfur atoms (yellow)
The characteristic trilayer structure of MoS₂ (S-Mo-S)