COMPARATIVE-STUDY OF I-V CHARACTERISTICS OF THE ICB DEPOSITED AG N-SI(111) AND AG/P-SI(100) SCHOTTKY JUNCTIONS/

The room temperature I-U characteristics of the ionized cluster beam, ICB, deposited Ag/n-Si(111) and Ag/p-Si(100) Schottky barrier junction s, for non zero Ag ions acceleration voltage U-a > 0 V, have been inve stigated. The effective Schottky barrier height (SBH) is observed to d ecrease if Ag is deposited on n-doped Si substrate but for Ag/p-Si jun ction shows an increase, relatively to the corresponding SBH values of U-a = 0 V ICB deposited junctions, respectively. The accelerated Ag m etal ions, an essential characteristic of the ICE deposition method ma y for an appropriate value of U-a penetrate the Si wafer a few nm in d epth and consequently might strongly contribute to an additional dopin g density within this-Ag enriched-Si region. For the penetration lengt h L of the order of a few Si lattice lengths the penetrating energetic Ag ions are producing, before embedded within the substrate, some lat tice structural damages what effectively results in the fact, that the Ag enriched silicon region may approximately be considered as the spe cific case of the disordered interface control layer, ICL. The modific ation of the Ag/Si energy bands due to the existence of this ICL in co njunction with the assumed DIGS electron charge density, occurring in the presumably abrupt plane between the Ag enriched region and the res t of the bulk Si substrate, has been calculated. On the basis of the o btained results, a tentative suggestion is advanced according to which the semiconductor local energy band modification (occurring as the si multaneous result of activated Ag deep impurity levels in the Si wafer and the appearance of localized charges due to DIGS) is to largest de gree responsible for an effective unpinning of the semiconductor Fermi level inducing, in such a way, the modulation of the Schottky barrier height. (C) 1998 Elsevier Science Ltd. All rights reserved.