Recoil implantation method for ultrashallow p+/n junction formation

Abstract

A recoil implantation technique is investigated for ultrashallow p ϩ /n junction formation. In this method, a 3-35 nm thick B layer is deposited on the wafer by magnetron sputtering. Then a medium energy ͑10-40 keV͒ Ge implant drives the boron atoms into Si by means of ion beam mixing. The remainder of the boron film is chemically etched away prior to the annealing step. Sub-60 nm deep p ϩ /n junctions with sheet resistance less than 1000 ⍀/sq and test diodes with leakage current density below 2 nA/cm 2 have been formed using this method.