Characteristics of n(+) polycrystalline-Si/Al2O3/Si metal-oxide-semiconductor structures prepared by atomic layer chemical vapor deposition using Al(CH3)(3) and H2O vapor

We report interface and dielectric reliability characteristics of n(+) poly crystalline-silicon (poly-Si)/Al2O3/Si metal-oxide-semiconductor (MOS) capa citors. Al2O3 films were prepared by atomic layer chemical vapor deposition using Al(CH3)(3) and H2O vapor. Interface state density (D-it) and dielect ric reliability properties of n(+) poly-Si/Al2O3/Si MOS structures were exa mined by capacitance-voltage, conductance, current-voltage, and time-depend ent dielectric breakdown measurements. The D-it of the n(+) poly-Si/Al2O3/S i MOS system near the Si midgap is approximately 8 x 10(10) eV(-1) cm(-2) a s determined by the conductance method. Frequency dispersion as small as si milar to 20 mV and hysteresis of similar to 15 mV were attained under the e lectric field of +/-8 MV/cm. The gate leakage current of similar to 36 A ef fective thickness Al2O3 dielectric measured at the gate voltage of -2.5 V i s similar to -5 nA/cm(2), which is approximately three orders of magnitude lower than that of a controlled oxide (SiO2). Time-dependent dielectric bre akdown data of Al2O3/Si MOS capacitors under the constant current/voltage s tress reveal excellent charge-to-breakdown characteristics over controlled oxide. Reliable gate oxide integrity of Al2O3 gate dielectric is manifested by the excellent distribution of gate oxide breakdown voltage on 128 milli on MOS capacitors having isolation edges. Extracted time constant and captu re cross section of the Al2O3/Si junction are discussed. (C) 2001 American Institute of Physics.