Comparison on atomic/molecular layer deposition grown aluminum alkoxide polymer films using alkane and alkyne organic precursors

Most hybrid films grown by atomic and molecular layer deposition (ALD and MLD) at relatively low temperatures commonly incorporate aliphatic organic bifunctional hydrocarbons as their organic counterparts. This often results in “double reactions” leading to lower growth rates, relatively poor film quality, and atmospherically unstable hybrid films. Although such a drawback has been overcome in the past using three-step ABC reactions, aromatic organic precursors, and heterobifunctional precursors, each has displayed one or the other limitations of growth. In this work, the possibility of overcoming double reactions during hybrid film growth by MLD at relatively low temperatures using an sp-hybridized carbon backbone organic precursor is explored. 1,4-butynediol (BDy) along with trimethylaluminum (TMA) is used to deposit “alucone” films at 80 °C. A comparison on growth and properties of the resultant film is drawn with another alucone film deposited using alkane based hydrocarbon, 1,4-butanediol (BD). In situ quartz crystal microbalance and fourier transform infrared (FTIR) spectroscopy studies are performed to determine and compare the growth and surface chemistry of the deposited films. Unfortunately, TMA-BDy films show similar growth characteristics to TMA-BD ones. A 2:1 stoichiometry of growth is observed not only for TMA-BD but also for TMA-BDy films. This shows the occurrence of double reactions irrespective of the carbon–carbon linkages for the linear homobifunctional organic precursors used. A detailed understanding of the stability issue of the deposited hybrid films is further obtained utilizing ex situ FTIR and x-ray reflectivity measurements in this work.