Patent ID: 6096586
Filing Date: 2000-08-01
Classification: H01L

Abstract:
A method of fabricating a MOS device having self-compensating implant regions, said method comprising the steps of:providing a semiconductor substrate of a first conductivity type;performing a partial first threshold implant of dopant pf the first conductivity type at a dose between about 2.times.10.sup.12 and 4.times.10.sup.12 ions/cm.sup.2 and at an energy about 5-15 KeV with a low tilt angle of 7.degree. so as to form a higher concentration layer on said semiconductor substrate which is higher than said substrate;forming a gate oxide on a surface of said higher concentration layer;forming a gate on a surface of said gate oxide;performing subsequent to the gate formation a second threshold adjust implant of dopant of the first conductivity type at a dose of about 1.times.10.sup.13 and 8.times.10.sup.13 ions/cm.sup.2 and at an energy about 2-5 KeV with a low tilt angle of 0.degree.-7.degree. so as to form self compensating implant regions in said higher concentration layer on opposite sides of said gate;said self-compensating implant regions creating a lateral non-uniform channel doping which compensates for variations in the length of the gate;heating subsequent to the second threshold adjust implant said substrate with self-compensating implant regions so as to cause lateral diffusion in said higher concentration layer and under said gate to define pockets from each side of the gate in which source/drain regions will be subsequently formed;said heating being used to control the level of the lateral non-uniform channel doping so as to compensate for the variations in the length of the gate; performing a third implant of a second conductivity type so as to create lightly-doped source/drain regions in said pockets on opposite sides of said gate;forming a sidewall spacer on each side of said gate; andperforming a fourth implant of the second conductivity type through said gate and said gate oxide so as to create highly-doped source/drain regions between said lightly-doped source/drain regions and said pockets.