Atomic layer deposition of molybdenum oxide using (N Bu)2(NMe2)2Mo, hydrogen peroxide (H2O2), and ozone (O3) for DRAM application

Molybdenum oxide (MoO x ) films have the unique characteristics of a number of possible structures and high work functions. In DRAM using high-k dielectrics, MoO x can be used to reduce leakage current that originates from Schottky emission. High quality MoO x can be deposited using atomic layer deposition (ALD) that is advantageous in terms of the resulting film's high uniformity, high conformality, and precise thickness controllability. In this work, MoO x films were deposited using bis(tert-butylimido)-bis(dimethylamido)molybdenum ((N t Bu) 2 (NMe 2 ) 2 Mo) as a metal precursor, and hydrogen peroxide (H 2 O 2 ) and ozone (O 3 ) as oxidants. The MoO x films were deposited between 100 and 300 °C growth temperature. MoO x deposited at 200 °C using H 2 O 2 and O 3 shows different GPC values of 0.08 and 0.20 Å/cycle, respectively, due to the different reactivities of the oxidants. The O/Mo ratio, atomic concentration of impurities, crystallinity, optical properties, work function, and sheet resistance of TiN altered by MoO x fabricated using H 2 O 2 and O 3 were investigated. The reactivity of O 3 is higher than that of H 2 O 2 , which increases the sheet resistance of TiN by 23.1%. Finally, a cross section of MoO x deposited with H 2 O 2 on a trench wafer was investigated to demonstrate conformal deposition onto a complex structure.