強誘電体PZTのMOCVD成長(<小特集>酸化物のエピタキシー)

抄録

Lead Zirconate Titanate (Pb(Zr,Ti)0_3) thin films were depositied on Pt films by metal-organic chemical vapor deposition (MOCVD). Three sources of Pb(DPM)_2, Zr(DPM)_4, and Ti(i-OC_3H_7)_4 were supplied using nitrogen carrier gas and thermally decomposed on the substrate at about 550℃ and 5 Torr of oxidizing atmosphere. The good composition control resulting from the use of Zr(DPM)_4 provided in-depth uniformity near the interface between electrode platinum and deposited film. The variation of composition over a 4" wafer was about 1% achieved by optimizing the source supply and pumping system. These films were less than 100 nm thin enough for LSI memory application. Even 80 nm thick films showed a good ferroelectric hysteresis characteristics with low coecive voltage of O.7V. The dielectric characteristics for application of dynamic random access memories (DRAM) was equvalent to O.4nm of Si0_2 with 2×l0^<-7> A/cm^2 at 1.5v.