Methods for reducing wordline sheet resistance
AssigneeMacronix International Co., Ltd.
InventorsHung-Wei Liu, Hsueh-Hao Shih, Szu-Yu Wang
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Abstract
The present invention is directed to forming memory wordlines having a relatively lower sheet resistance. In one embodiment, a first poly-Si portion is deposited on a semiconductor substrate using a first precursor gas flow rate. A second poly-Si portion is deposited using a second precursor gas flow rate, where the second precursor flow rate higher than the first precursor gas flow rate. A tungsten silicide layer is deposited using silane gas. Wordlines are formed in trenches from poly-Si and WSix. A gate electrode is implanted.
Claims36
A method of forming memory wordlines, the comprising:
- forming a first gate dielectric;
- forming a charge storage layer on the first gate dielectric;
- forming a second dielectric layer on the charge storage layer;
- depositing a first poly-Si portion using a gas with a first gas flow rate;
- depositing a second poly-Si portion using the gas with a second gas flow rate, the second gas flow rate higher than the first gas flow rate;
- depositing a tungsten silicide layer with silane gas, wherein wordlines are formed in isolation trenches from a stacked film of poly-Si and tungsten silicide;
- and
- implanting a gate electrode.
A method of depositing tungsten to form wordlines, the method comprising:
- depositing on the semiconductor substrate a first poly-Si portion with a first precursor gas flow rate;
- depositing a second poly-Si portion with a second precursor gas flow rate, the second precursor flow rate higher than the first precursor gas flow rate;
- performing gate implantation using an implantation energy within the range of about 30 to 100 KeV;
- and
- depositing a WSix layer, wherein wordlines are formed from poly-Si and WSix.
A method of forming memory wordlines, the method comprising:
- depositing a first poly-Si portion using a gas with a first gas flow rate;
- depositing a second poly-Si portion using the gas with a second gas flow rate, the second gas flow rate higher than the first gas flow rate;
- depositing WSix and forming wordlines;
- and
- implanting a gate electrode.
Dependencies are inferred from the claim text.