DIAMOND-LIKE CARBON-FILM PREPARATION AND SURFACE-COATINGS OF OXIDE SUPERCONDUCTING AND FERROELECTRIC-FILMS

Diamond-like carbon (DLC) films as well as amorphous carbon films are investigated as possible passivation and environment protection for YB a2Cu3O7-x (YBCO) oxide superconducting and Pb(ZrxTi1-x)O-3 (PZT) ferro electric thin films. The pulsed laser deposition (PLD) technique was e mployed to prepare the perovskite oxide films of YBCO and PZT. These f ilm surfaces were coated by the DLC films prepared using the excimer l aser ablation method. Optimum deposition condition of the PLD process for the YBCO, PZT and DLC was investigated. In the case of DLC coating s, a graphite target was ablated using a KrF excimer laser of 2-9 J cm (-2) in 200-800 mTorr hydrogen ambient gas. An optical band gap of 2.0 eV was attained on room temperature substrate and high quality superc onductivity of the DLC coated YBCO films was kept over 1 month. The PZ T film encapsulated by the DLC layer showed no degradation due to agin g over 30 days. (C) 1998 Elsevier Science Ltd. All rights reserved.