Patent ID: 6025239
Filing Date: 2000-02-15
Classification: H01L

Abstract:
A method for fabricating an electrostatic discharge device on a semiconductor substrate of a first conductivity type, comprising the steps of:successively forming a gate dielectric layer and a gate electrode over the semiconductor substrate;forming a first lightly-doped region of a second conductivity type in the semiconductor substrate through a first ion implantation step which uses the gate electrode as a mask with the first lightly doped region having a first dopant concentration;after forming the first lightly-doped region, forming a second lightly-doped region of the second conductivity type, with a second dopant concentration and deeper than the first lightly-doped region, directly in the semiconductor substrate without any other doped region between the second lightly doped region and the semiconductor substrate, through a second ion implantation step which uses the gate electrode as a mask and increases the first dopant concentration, resulting in the first lightly doped region having a higher dopant concentration than the second lightly doped region;forming a sidewall spacer on sidewalls of the gate dielectric layer and the gate electrode; andforming a heavily-doped region of the second conductivity type directly in the semiconductor substrate without any other doped region between the second lightly doped region and the semiconductor substrate, through a third ion implantation step which uses the gate electrode and the sidewall spacer as a mask.