摘要 |
The present invention is related to methods and apparatus for processing weak ferroelectric films on semiconductor substrates, including relatively large substrates, e.g., with 300 millimeter diameter. A ferroelectric film of zinc oxide (ZnO) doped with lithium (Li) and/or magnesium (Mg) is deposited on a substrate in a plasma assisted chemical vapor deposition process such as an electron cyclotron resonance chemical vapor deposition (ECR CVD) process. Zinc is introduced to a chamber through a zinc precursor in a vaporizer. Microwave energy ionizes zinc and oxygen in the chamber to a plasma, which is directed to the substrate with a relatively strong field. Electrically biased control grids control a rate of deposition of the plasma. The control grids also provide Li and/or Mg dopants for the ZnO to create the ferroelectric film. A desired ferroelectric property of the ferroelectric film can be tailored by selecting an appropriate composition of the control grids.
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