Browse Prior Art Database

Silicided Source/ 0rain Process for MOSFET

IP.com Disclosure Number: IPCOM000121215D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Sasaki, K: AUTHOR

Abstract

Disclosed is a process for high performance MOSFET (DRAM memory cell) using silicided source/drain, silicided gate and polysilicon pad for metal contact.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 99% of the total text.

Silicided Source/ 0rain Process for MOSFET

      Disclosed is a process for high performance MOSFET (DRAM
memory cell) using silicided source/drain, silicided gate and
polysilicon pad for metal contact.

      A process sequence to manufacture the DRAM cell consists of the
following steps:
 1) Forming trench capacitors.
 2) Growing ROX (recessed oxide) isolation and gate oxide.
 3) Depositing N-type polysilicon, tangsten silicide WSi2, LPCVD-SiO2
and patterning gate electrode.
 4) Forming oxide spacer on gate electrode edges.
 5) Implanting N/PMOSFET source/drain.
 6) Forming silicide on source/drain.
 7) Depositing polysilicon film and patterning polysilicon pad.
 8) Depositing blanket CVD insulator film.
 9) Etching contact holes, depositing and patterning metal level (*).
The figure shows a cross section of the new DRAM memory cell.

      This process has four advantages:
 1) In self-aligned silicide formation, it is prevented that shorts
between gate and diffusion regions occur due to silicide residues.
 2) Diffusion and gate material sheet resistances can be designed
independently.
 3) As this process enables increase of overlay margin around
contact, the area of DRAM memory cell is smaller.
 4) Connection of trench capacitor and MOSFET drain is stabilized
easily.

      Reference
(*)  N. C. C. Lu, et al., "A Substrate-Plate Trench-Capacitor (SPT)
Memory Cell for Dynamic RAM's," IEEE Journal of Solid-State Circuits
SC-21, 5, 627-634 (Octo...