Gate structure and method of making the same
AssigneeUnited Microelectronics Corp.
InventorsChing-Hung Kao, Chien-En Hsu
Life of this patent
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Abstract
A method of making a gate structure includes the following steps. First, a gate is formed. Then, a first silicon oxide layer, a silicon nitride layer, and a second silicon oxide layer are formed to cover the gate from bottom to top. Later, a dry etching is performed to etch the second silicon oxide layer. After that, a wet etching is performed to etch the silicon nitride layer and the first silicon oxide layer. The aforesaid wet etching is performed by utilizing an RCA cleaning solution. Furthermore, the silicon nitride layer is formed by the SINGEN process. Therefore, the first and second silicon oxide layer and the silicon nitride layer can be etched together by the RCA cleaning solution.
Claims12
A method of forming a gate structure, comprising:
- forming a gate;
- forming a first silicon oxide layer, a silicon nitride layer and a second silicon oxide layer covering the gate from bottom to top;
- performing a dry etching process to etch the second silicon oxide layer;
- and
- performing a wet etching process to etch the silicon nitride and the first silicon oxide layer.
A gate structure, comprising:
- a gate;
- and
- a spacer positioned at a sidewall of the gate, the spacer comprising an oxide-nitride-oxide (ONO) stack layer formed by a first silicon oxide layer, a silicon nitride layer and a second silicon oxide layer, the silicon nitride layer unetched by phosphoric acid so that an undercut does not occur in the silicon nitride layer.
Dependencies are inferred from the claim text.