Browse Prior Art Database

Method for Making Lightly Doped Drain Shallow Junctions

IP.com Disclosure Number: IPCOM000036490D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Pan, P: AUTHOR

Abstract

By using a removable tungsten edge spacer, an L-shaped oxide film is formed to define the position of heavily doped and lightly doped drain regions without photo-masking.

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Method for Making Lightly Doped Drain Shallow Junctions

By using a removable tungsten edge spacer, an L-shaped oxide film is formed to define the position of heavily doped and lightly doped drain regions without photo-masking.

Referring to Fig. 1, standard processing is used to form gate oxide (SiO2) 2 on silicon substrate 4 and overlying gate conductor 6 with cap silicon nitride (Si3N4) layer 8. Conformal layers of SiO2 10 and tungsten (W) 12 are then deposited.

The cross section (Fig. 2) is the result of the anisotropic etching of the W layer 12 at least until the SiO2 layer 10 is completely exposed in flat horizontal areas, and then anisotropically etching away the SiO2 layer 10 in those areas.

Referring to Fig. 3, standard processing is next used to form cobalt disilicide (CoSi2) source and drain contacts 14. The remaining W 12 is then selectively etched away. Ion implantation and annealing are used to form lightly doped regions 18 and heavily doped regions 20. The devices are completed by standard processing.

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