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US5364807A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for fabricating LDD transitor utilizing halo implant

Assignee: Chung Cheng Holding LLC
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Filing: 1993-10-12
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Granted: 1994-11-15
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Expires: 2013-10-12
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Abstract

Abstract A method for fabricating an asymmetry HS-GOLD MOSFET by use of a photo etch process in place of a large tilt implantation process, capable of improving a packing density and reducing a junction capacitance of a source region, thereby improving a characteristic of a device to be finally produced. The method includes the steps of forming a gate insulating film and a gate on a p - type semiconductor substrate, implanting n type impurity ions in the semiconductor substrate so as to symmetrically form n - type source and drain regions in the semiconductor substrate, forming an insulating film over the entire exposed surface of the resulting structure, subjecting the insulating to an anisotropic etching to form spacers at respective side walls of the gate, implanting n type impurity ions in the semiconductor substrate so as to form n + type high concentration source and drain regions respectively adjacent to the n - type source and drain regions, coating a photoresist film over the entire exposed surface of the resulting structure, subjecting the photoresist film to a patterning to expose one of the spacers disposed toward the source region, removing the exposed spacer, and implanting p type impurity ions in the semiconductor substrate through an area defined by removal of the spacer so as to form a p type halo region.

Inventors

  • 👤 Hyun S. Hwang

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-28 09:59
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/13; H10D62/149; H10D62/151; H10D30/00; H10D30/01; H10D30/021; H10D30/0223; H10D30/0227; H10D30/022; H10D30/0221; H10D30/60; H10D30/601; H10D30/603; H10D62/17; H10D62/351; H10D62/357; H10D62/364; H10D62/371; H10D64/00; H10D64/01; H10D64/015

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 232 words
A method for fabricating a transistor comprising the steps of: forming a gate insulating film and a gate on a low concentration semiconductor substrate of a first conductivity type; implanting impurity ions of a second conductivity type in said semiconductor substrate under a condition that said gate is used as a mask so as to symmetrically form low concentration source and drain regions of said second conductivity type in the semiconductor substrate; forming an insulating film over the entire exposed surface of the resulting structure, and subjecting said insulating to an anisotropic etching to form spacers at respective side walls of the gate; implanting impurity ions of said second conductivity type in the semiconductor substrate under a condition that said spacers and gate are used as a mask so as to form high concentration source and drain regions of the second conductivity type respectively adjacent to said low concentration source and drain regions; coating a photoresist film over the entire exposed surface of the resulting structure, and subjecting said photoresist film to a patterning to expose one of the spacers disposed toward the low concentration source region; removing said exposed spacer; and implanting impurity ions of said first conductivity type in the semiconductor substrate through an area defined by removal of the spacer so as to form a p type halo region in a region occupied by the low concentration source region.
Claim 2
Independent Claim 232 words
A method for fabricating a transistor comprising the steps of: forming a gate insulating film and a gate on a low concentration semiconductor substrate of a first conductivity type; implanting impurity ions of a second conductivity type in said semiconductor substrate under a condition that said gate is used as a mask so as to symmetrically form low concentration source and drain regions of said second conductivity type in the semiconductor substrate; forming an insulating film over the entire exposed surface of the resulting structure, and subjecting said insulating to an anisotropic etching to form spacers at respective side walls of the gate; implanting impurity ions of said second conductivity type in the semiconductor substrate under a condition that said spacers and gate are used as a mask so as to form high concentration source and drain regions of the second conductivity type respectively adjacent to said low concentration source and drain regions; coating a photoresist film over the entire exposed surface of the resulting structure, and subjecting said photoresist film to a patterning to expose one of the spacers disposed toward the low concentration source region; removing said exposed spacer; and implanting impurity ions of said first conductivity type in the semiconductor substrate through an area defined by removal of the spacer so as to form a p type halo region in a region occupied by the low concentration source region.
Claim 3
Dependent Claim 31 words
A method in accordance with claim 1, wherein said exposure of one of the spacers disposed toward the low concentration source region is achieved by use of a tri-level resist process.
Claim 4
Dependent Claim 135 words
A method in accordance with claim 2, wherein said exposure is achieved by the steps of: coating a tri-level photoresist film including a lower photoresist film, an SOG film and an upper photoresist film over the entire exposed surface of the resulting structure after the formation of said high concentration source and drain regions; subjecting said upper photoresist film to a patterning using a photolithography process; subjecting said SOG film to a patterning under a condition that said patterned upper photoresist film is used as a mask; removing the remaining upper photoresist film; etching said lower photoresist film under a condition that said patterned SOG film is used as a mask so as to expose said spacer disposed toward the low concentration source region; and sequentially removing the remaining SOG film and lower photoresist film.

References Cited (Backward Citations)

JPS5671971A Cited
DD244853A1 Cited
DD279351A1 Cited
USH986H Cited
US5043294A Cited
US5296398A Cited
US5063172A Cited
JPH04115538A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1997-11-14 1998-05-16 1998-11-15 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2001-11-14 2002-05-16 2002-11-15 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2005-11-14 2006-05-16 2006-11-15 $7700.00 Window Closed / Lapsed

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