Patent ID: 9576914
Date: 2017-02-21
CPC Classifications: H01L

Claim:
1. A method of forming a Physically Unclonable Function (PUF) semiconductor device, the method comprising: defining a first and second region on a substrate, the first region includes a first implant region and a first covered region subject to being covered, the second region includes a second implant region and a second covered region subject to being covered, the first implant region has a first width, the second implant region has a second width, and the first width is greater than the second width; forming a shallow trench isolation (STI) in the substrate, wherein the STI is on adjacent sides of the first region and adjacent sides of the second region; forming a patterned mask on the first covered region and on the second covered region; forming a first implant well in the first implant region and a second implant well in the second implant region; annealing the first implant well and the second implant well, wherein the first implant region and the first covered region have a first uniform dopant concentration, and the second implant region and the second covered region have a second uniform dopant concentration, wherein the first uniform dopant concentration is greater than the second uniform dopant concentration; forming a first device on the first region and a second device on the second region, wherein the method is performed so that a difference in the first uniform doping concentration and the second uniform doping concentration varies in dependence on a difference between the first width and the second width; and wherein the method is performed so that random variation in the method of forming the semiconductor device results in the first implant region having the first width, and the second implant region having the second width.