Thin films of ZrO 2 and HfO 2 have been deposited by liquid injection metal±organic (MO)CVD using a range of new alkoxide precursors, [Zr(O t Bu) 2 (mmp) 2 ] (1), [Hf(O t Bu) 2 (mmp) 2 ] (2), [Zr(mmp) 4 ] (3), and [Hf(mmp) 4 ] (4): (mmp = 1-methoxy-2-methyl-2-propanolate, OCMe 2 CH 2 OMe). The complexes are mononuclear and volatile, and are significantly less reactive to air and moisture than existing Zr and Hf alkoxide precursors such as [Zr(O t Bu) 4 ] and [Hf(O t Bu) 4 ]. The ZrO 2 and HfO 2 films were grown over a wide range of substrate temperatures (350±650 C), and analysis by laser Raman spectroscopy shows that the films were deposited in the thermodynamically stable a-or monoclinic phase.

Thin films of hafnium oxide (HfO 2 ), gadolinium oxide (Gd 2 O 3 ), and praseodymium oxide (PrO x ) have been deposited by liquid injection atomic layer deposition (ALD) and for comparison, have also been deposited by ªthermalº metal-organic (MO) CVD using the same reactor. The ALD-grown films were deposited on Si(100) over a range of substrate temperatures (150±450 C) using alternate pulses of [Hf(mmp) 4 ], [Gd(mmp) 3 ], or [Pr(mmp) 3 ] (mmp = OCMe 2 CH 2 OMe) and water vapor. X-ray diffraction (XRD) analysis showed that as-grown films of HfO 2 were amorphous, but these crystallized into the monoclinic phase after annealing in air at 800 C. XRD analysis showed that as-grown Gd 2 O 3 and PrO x films had some degree of crystallinity. Residual carbon (0.8±3.3 at.-%) was detected in the HfO 2 and PrO x films by Auger electron spectroscopy (AES), but not in the Gd 2 O 3 films. The self-limiting behavior of the precursors was investigated at 225 C by varying the volume of precursor injected during each ALD cycle and, in each case, oxide growth was not fully self-limiting. We propose a mechanism for this involving b-hydride elimination of the mmp group, and also propose some general mechanistic principles which may influence the growth of oxides by ALD using other precursors.

A number of high-permittivity (j) dielectric oxides are currently being investigated as alternatives to SiO 2 as the dielectric insulating layer in sub-0.1 lm CMOS technology. Metal-organic (MO)CVD and atomic layer deposition (ALD) are promising techniques for the deposition of these high-j dielectric oxides. In this paper it is shown how the use of "designed" metal alkoxide precursors, containing bidentate donor-functionalized alkoxide ligands, in MOCVD leads to a marked improvement in the physical properties of the MOCVD precursors and process parameters. However, the use of such ligands is not as beneficial in the ALD process, highlighting the very different requirements of MOCVD and ALD precursors.

4 ]. Varying levels of residual carbon and nitrogen were detected in the films grown from each precursor. Analysis by X-ray diffraction (XRD) indicates that films grown from both precursors exist predominantly in the thermodynamically stable monoclinic phase. Scanning electron microscopy (SEM) shows that the morphology of the HfO 2 films from each precursor is markedly different, with films deposited from [Hf(NMe 2 ) 4 ] having a well-defined columnar crystalline structure, whereas films grown from [Hf(ONEt 2 ) 4 ] are smoother with little evidence of columnar structure. Full crystal structure data for [Hf(NMe 2 ) 4 ] are given, and the dielectric properties of [Al/HfO 2 /n-Si(100)] MOS capacitors, fabricated using each precursor, are also reported.

Thin films of praseodymium oxide have been deposited by liquid injection MOCVD using the volatile praseodymium alkoxide, [Pr(mmp) 3 ] (mmp = 1-methoxy-2-methyl-2-propanolate, OCMe 2 CH 2 OMe). The films were grown over a wide range of substrate temperatures (250±600 C) and were found to consist predominantly of the Pr 6 O 11 phase. Praseodymium silicate films containing~16±22 at.-% Si were deposited over the temperature range 350±550 C using [Pr{N(SiMe 3 ) 2 } 3 ] in the absence of any additional Si source.