Behavior of Electrodeposited Cd and Pb Schottky Junctions on CH3-Terminated n-Si(111) Surfaces

n-Si/Cd and n-Si/Pb Schottky junctions have been prepared by electrodeposition of Cd or Pb from acidic aqueous solutions onto H-terminated and CH3-terminated n-type Si 111 surfaces. For both nondegenerately nand degenerately n+doped H–Si 111 electrodes, Cd and Pb were readily electroplated and oxidatively stripped, consistent with a small barrier height b at the Si/solution and the Si/metal junctions. Electrodeposition of Cd or Pb onto degenerately doped CH3-terminated n +-Si 111 electrodes occurred at the same potentials as Cd or Pd electrodeposition onto H-terminated n+-Si 111 . However, electrodeposition on nondegenerately doped CH3-terminated n-Si 111 surfaces was significantly shifted to more negative applied potentials by −130 and −347 mV, respectively , and the anodic stripping of the electrodeposited metals was severely attenuated, indicating large values of b for contacts on nondegenerately doped n-type CH3–Si 111 surfaces. With either Cd or Pb, current–voltage measurements on the dry, electrodeposited Schottky junctions indicated that much larger values of b were obtained on CH3-terminated n-Si 111 surfaces than on H-terminated n-Si 111 surfaces. Chronoamperometric data indicated that CH3–Si 111 surfaces possessed an order-of-magnitude lower density of nucleation sites for metal electrodeposition than did H–Si 111 surfaces, attesting to the high degree of structural passivation afforded by the CH3–Si surface modification. © 2008 The Electrochemical Society. DOI: 10.1149/1.3021450 All rights reserved.