Patent ID: 8324099
Filing Date: 2012-12-04
Classification: H01L,Y10S

Abstract:
1. A method of fabricating a landing plug in a semiconductor memory device, comprising: forming a landing plug contact hole on a semiconductor substrate having an impurity region to expose the impurity region; forming a landing plug by filling the landing plug contact hole with a polysilicon layer, wherein the landing plug comprises a first region, a second region, a third region, and a fourth region, wherein the first region is disposed beneath the second region and doped with a first doping concentration, the second region is disposed above the first region and below the third region and is not doped, the third region is disposed above the second region and below the fourth region and is doped with a second doping concentration that is lower than the first doping concentration, and the fourth region is disposed above the third region and is doped with a third doping concentration that is higher than the first doping concentration; and annealing the resulting product formed with the landing plug.