Deep level transient spectroscopy of interfacial traps at ion-implanted ultrahigh p-Si Schottky barriers

Sequential implantation of Ar and low-energy H produces a high (0.83 eV), near-ideal Schottky barrier for Al deposited on p-Si. Deep level transient spectroscopy (DLTS) measurements reveal majority-carrier interfacial traps due to the implantation steps. Without H, Ar implantation alone results in an interfacial trap doublet at 0.48 eV with high emission rates. Such samples display an elevated barrier relative to the implanted control samples, but with serious leakage current. When H implant is added, however, only a single interfacial trap, with a very low emission rate, is present at 0.47 eV. Thus DLTS suggests that H may idealize the barrier by substituting interfacial traps having reduced charge transport rate, so that there is less competition with thermionic emission.