Etch Gas for Polysilicon Silicon Oxide (Nitride) Composite Structures
Original Publication Date: 1980-Mar-01
Included in the Prior Art Database: 2005-Feb-13
In the reactive ion etching of polysilicon layers where overlying or underlying layers of silicon dioxide and/or silicon nitride layers are present, a larger than normal etch rate ratio is achieved by employing about 50/50 mixtures of oxygen and carbon tetrachloride for etching and etching at an elevated substrate temperature. The polysilicon layers can, therefore, be etched without significant attack on the silicon oxide or nitride layers. The data in the table below provides a comparison. See Original.