Patent ID: 7358168

Claim:
An ion-implantation method for forming a shallow junction, comprising: providing a semiconductor substrate including at least one transistor structure, and at least one transistor structure having at least one gate electrode and at least one implantation region for forming one of drain and source electrodes of the transistor structure thereon; forming an oxide layer on the transistor structure; etching the oxide layer to form at least one gate spacer on the at least one gate electrode; removing the oxide layer located on the at least one implantation region; forming a buffer layer on the at least one implantation region and the at least one gate spacer, the buffer layer having a predetermined thickness; implanting charged ions into the at least one implantation region through the buffer layer by an energy provided by a middle-energy ion implanter; and removing the buffer layer over the at least one implantation region and the at least one gate spacer.