Chartered Semiconductor Manufacturing Ltd (Corporation)

Yun Qiang Zhang

James Yong Meng Lee

Ravi Sundaresan

Chock Hing Gan

Xia Li

A new method is provided for the creation of ultra-thin gate oxide layers. Under the first embodiment, sacrificial oxide and nitride are deposited, openings are created in the layer of nitride where the ultra-thin layer of gate oxide is to be created. A layer of poly is deposited over the layer of nitride. The layer of polysilicon is polished, leaving the poly deposited inside the openings. The nitride is removed leaving the gate structure in place overlying the grown gate oxide. Under the second embodiment, sacrificial oxide and nitride are deposited followed by the deposition of TEOS oxide. The layers of TEOS, oxide and nitride are patterned creating openings that expose the surface areas of the layer of sacrificial oxide where the ultra-thin layers of gate oxide are to be grown. A thin conformal layer of nitride is deposited over the structure, this thin layer of conformal nitride is etched to form thin spacers on the sidewalls of the openings in the layers of TEOS oxide and nitride. Pre-gate clean is performed that removes the TEOS oxide and the sacrificial oxide on the bottom of the openings, gate oxidation is performed creating the ultra-thin layers of gate oxide. Poly is deposited, polished back followed by removal of the nitride leaving the poly gate structure in place and overlying the ultra-thin layer of gate oxide.

Method of patterning gate electrode with ultra-thin gate dielectric

A buffer layer and a gate dielectric layer overlying a substrate having at least one active area is provided. A sacrificial oxide layer is formed over the gate dielectric layer. A nitride layer is formed over the sacrificial oxide layer. The nitride layer is patterned to form an opening therein within the active area exposing a portion of the sacrificial oxide layer within the opening. The portion of the sacrificial oxide layer within the opening is stripped, exposing a portion of the underlying gate dielectric layer within the opening. A gate electrode is formed within opening over the portion of the gate dielectric layer. The remaining nitride layer is selectively removed. The remaining sacrificial oxide layer is then stripped and removed.

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Singapore, Singapore

Yun Qiang Zhang