HIGH-BARRIER HEIGHT SCHOTTKY DIODES ON N-INP BY DEPOSITION ON COOLED SUBSTRATES

Ultrahigh barrier height (phi-B = 0.96 eV) Schottky contacts to n-InP, without an intentionally grown interficial oxide, were formed using metal deposition on a substrate cooled to as low as 77 K [low temperature (LT)]. Phi-B = 0.46-0.52 eV for diodes deposited at room temperature (RT = 300 K) agree well with previously published results, and give an ideality factor near unity. For the diodes deposited at LT = 77 K, the leakage current density (J0) was reduced by more than 6-7 orders of magnitude with respect to the RT diodes. The phi-B for the LT diodes was increased from 0.48 to 0.96 eV for Pd metal and from 0.51 to 0.85 eV for Au metal, respectively. An alteration of the metal-induced interface states, inhibition of surface segregation of the released In and P atoms, and very uniform metal coverage may be responsible for the distinct differences between the RT and LT diodes.