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Questions and Answers
What is the primary function of the heating coils in a CVD system?
What is the primary function of the heating coils in a CVD system?
What is a characteristic of the deposited layer in a CVD process?
What is a characteristic of the deposited layer in a CVD process?
What is the purpose of the susceptor in a CVD system?
What is the purpose of the susceptor in a CVD system?
What type of materials can be grown using CVD?
What type of materials can be grown using CVD?
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What is epitaxy in the context of CVD?
What is epitaxy in the context of CVD?
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What is a major advantage of using epitaxial films?
What is a major advantage of using epitaxial films?
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What is often used as a substrate for growing gallium nitride?
What is often used as a substrate for growing gallium nitride?
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What is an example of a non-epitaxial application of CVD?
What is an example of a non-epitaxial application of CVD?
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What is a key advantage of using gaseous precursors in CVD?
What is a key advantage of using gaseous precursors in CVD?
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What is a common application of CVD in modern fabrication?
What is a common application of CVD in modern fabrication?
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Study Notes
Chemical Vapor Deposition (CVD)
- CVD is a deposition of material on a substrate using chemistry, where a chamber encloses the vapor and energy is provided to the system, typically thermally or radiatively.
- A precursor is a chemical that causes deposition on the substrate, typically a one or two-component chemical that reacts to form the desired material.
- The deposited layer requires a substrate, which can be a wafer or any other substrate, and it sits on a susceptor that holds the wafer during deposition.
- Susceptors must have certain characteristics, including cleanliness, to facilitate the deposition process.
Characteristics of CVD Films
- CVD is used to deposit high-quality films with very low contamination, which can be epitaxial and single crystalline.
- Epitaxy refers to growing single crystalline material on top of an existing single crystalline material, with perfect lattice-matching and large grains with no or few grain boundaries.
Applications of CVD
- CVD is used to grow device-grade semiconducting materials, such as high-mobility transistors in modern CMOS fabrication.
- CVD is used to grow heterojunctions, such as germanium on silicon or titanium dioxide on silicon, where the deposited layer has a different material than the substrate.
- CVD is used to grow high-quality thin films, not necessarily crystalline or epitaxial, such as polysilicon electrodes in CMOS.
- CVD is used to deposit dielectrics, such as silicon nitride and silicon oxide, on top of metal or directly on native substrates.
Advantages of CVD
- CVD can deposit a very wide range of materials, limited only by the ability to provide a suitable precursor.
- Chemists have developed ways to convert virtually every element into a CVD precursor.
- Gaseous precursors can be highly purified, providing an added advantage for CVD.
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Description
Learn the fundamentals of Chemical Vapor Deposition (CVD), a process of depositing material on a substrate using chemistry. This lecture covers the basics of CVD, including the components of a CVD chamber and the energy sources used.
