Large-tilted-angle nitrogen implant into dielectric regions overlaying source/drain regions of a transistor

• US 5,516,707 A
• Filed: 06/12/1995
• Issued: 05/14/1996
• Est. Priority Date: 06/12/1995
• Status: Expired due to Term

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: VLSI Technology, Inc. (Koninklijke Philips N.V.)
• Inventors: Nowak, Edward D., Loh, Ying-Tsong, Ding, Lily
• Primary Examiner(s): Thomas, Tom
• Assistant Examiner(s): GURLEY, LYNNE ANN
• Application Number:
  US08/489,525
• Time in Patent Office: 337 Days
• Field of Search: 437/35, 437/24, 437/29
• US Class Current: 438/302
• CPC Class Codes: H01L 21/26506 in group IV semiconductors
• CPC Class Codes: H01L 21/26586 characterised by the angle between the ion beam and the crystal planes or the main crystal surface
• CPC Class Codes: H01L 21/28176 with a treatment, e.g. annealing, after the formation of the definitive gate conductor
• CPC Class Codes: H01L 21/28194 by deposition, e.g. evaporation, ALD, CVD, sputtering, laser deposition H01L21/28202 takes precedence
• CPC Class Codes: H01L 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material
• CPC Class Codes: H01L 29/6659 with both lightly doped source and drain extensions and source and drain self-aligned to the sides of the gate, e.g. lightly doped drain [LDD] MOSFET, double diffused drain [DDD] MOSFET

Abstract

A transistor is formed which has improved hot carrier immunity. On a substrate, between two source/drain regions, a gate region is formed over a dielectric region. An implant is used to dope the source/drain regions. After doping the source/drain regions, a tilted angle nitrogen implant is performed to implant nitrogen into areas of the dielectric region overlaying the drain/source regions of the transistor. The tilted angle nitrogen implant may be performed before or after forming spacer regions on sides of the gate region.

Claims

1. A method for producing a transistor, the method comprising the steps of:

(a) forming on a substrate between two source/drain regions, a gate region on top of a dielectric region, the dielectric region including areas which overlay the drain/source regions;

(b) performing an implant to dope the source/drain regions;

(c) performing a tilted angle nitrogen implant to implant nitrogen into the areas of the dielectric region overlaying the drain/source regions of the transistor; and

,

(d) forming spacer regions on sides of the gate region after the tilted angle nitrogen implant performed in step (c).

2. A method as in claim 1 wherein in step (c) the tilted angle nitrogen implant is performed at an angle of tilt of approximately 30 to 60 degrees.

3. A method as in claim 2 wherein the tilted angle nitrogen implant dose is approximately 10¹⁵ to 10¹⁶ atoms per square centimeter and the energy is approximately 30 KeV to 60 KeV.