Deep level transient spectroscopy of ultra shallow junctions in Si formed by implantation

We have carried out DLTS in highly doped p⁺n Ultra Shallow Junctions (USJ) in Si formed by ion implantation. The samples were implanted either with a 10keV or a 5keV B implant at a dose of 5*10 ¹⁵cm¹⁵. The 10keV sample was also implanted with P and the 5keV samples were implanted with P and increasing doses of As to simulate an USJ in an n-well. Due to the high P and/or As implant doses, it was observed that a band offset also exists between the n-type implanted region and the n-type starting material. Therefore these samples contain another depletion region apart from the expected p⁺n depletion region. However, the electric fields in these regions act in opposite directions assisting the profiling of different regions after careful selection of biasing conditions. A deep state is observed in the n-type region at E_C-0.34eV which has a complex Laplace DLTS signature, which has arisen due to the implantation process.