Vol. 82 (1992) ACTA PHY SICA POLONICA Α No 5 Proceedings of the XX' International School of Semiconducting Compounds, Jaszowiec 1992 DUAL ROLE OF TiN REACTION BARRIER IN GOLD BASED METALLIZATION TO GaAs A. PIOTROWSKA, E. KAMIŃSKA, M. GUZIEWICZ, J. ADAMCZEWSKA, Institute of Electron Technology, Al. Lotników 32/46, 02-668 Warszawa, Poland S. KWIATKOWSKI AND A. TUROS Institute of Nuclear Studies, Hoża 69, 00-682 Warszawa, Poland Reactively sputtered ΤiΝ films were evaluated as annealing cap im- proving the formation of Au(Zn) ohmic cοntact and as antidiffusion barrier protecting contact metallization and underlying GaAs against reaction with Au overlayers. PACS numbers: 73.40.Ns Presenting an interesting combination of properties such as high thermal stability, high electrical conductivity and hardness, good resistance to corrosion, ΤiΝ thin films are of great interest in various applications, such as the technology of coatings resistant to severe environments and the technology of advanced met- allizations for semiconductor devices [1-5]. In this paper we describe an approach for improving the reliability of multilayer gold based metallization on GaAs by applying TiN as a reaction barrier. ΤiΝ films were evaluated as: (1) an anneal- ing cap enabling formation of improved Au(Zn) ohmic contact to p-GaAs, and (2) a diffusion barrier protecting contact metallization and underlying GaAs from reacting with gold overlayers used for bonding and interconnection purposes. (100) GaAs wafers Zn doped to p = 1.2 x 10 18 cm-3 were used in the present experiments. Barrier ΤiΝ films were prepared by reactive RF bias magnetron sput- tering from Ti target in a Leybold L560 Universal Coating System with the base pressure of 1.5 x 10—6 hPa. Deposition was carried out in mixed Αr+N2 discharges with the flow rates of the individual gas adjusted by mass flow controllers. N/Ti ratios in as deposited films were measured using 2 MeV He+ Rutherford backscat- tering (RBS), while X-ray diffraction was used to determine lattice parameters and preferred orientation. Four-probe method was applied to evaluate electric sheet re- sistance of ΤiΝ films. Au(Zn) contact metallization was deposited by sequential evaporation of 40 nm Αu/40 nm Zn/274 nm Au layers; it needed a heat treatment for 3 min at 420°C to form an ohmic contact with p-GaAs. 150 nm thick Au films were used as contact overlayers. Since the sublimation of As is a strong driving force for thermally induced reaction between Au and GaAs, to prove the applicability of ΤiΝ as a reaction (857)