ATMOSPHERIC-PRESSURE CHEMICAL-VAPOR-DEPOSITION OF TIN FROM TETRAKIS(DIMETHYLAMIDO)TITANIUM AND AMMONIA

Near stoichiometric titanium nitride (TiN) was deposited from tetrakis (dimethylamido)titanium (TDMAT) and ammonia using atmospheric pressure chemical vapor deposition. Experiments were conducted in a belt furna ce; static experiments provided kinetic data and continuous operation uniformly coated 150-mm substrates. Growth rate, stoichiometry, and re sistivity are examined as functions of deposition temperature (190-420 degrees C), ammonia how relative to TDMAT (0-30), and total gas-flow rate (residence time 0.3-0.6 s). Films were characterized by sheet res istance measurements, Rutherford Backscattering Spectrometry, and X-Ra y Photoelectron Spectrometry. Films deposited without ammonia were sub stoichiometric (N/Ti < 0.6-0.75), contained high levels of carbon (C/T i = 0.25-0.40) and oxygen (O/Ti = 0.6-0.9), and grew slowly. Small amo unts of ammonia (NH3/TDMAT greater than or equal to 1) brought impurit y levels down to C/Ti < 0.1 and O/Ti = 0.3-0.5. Ammonia increased the growth rates by a factor of 4-12 at temperatures below 400 degrees C. Films 500 Angstrom thick had resistivities as low as 1600 mu Omega-cm when deposited at 280 degrees C and 1500 mu Omega-cm when deposited at 370 degrees C. Scanning electron micrographs indicate a smooth surfac e and poor step coverage for films deposited with high ammonia concent rations.