| AVS 57th International Symposium & Exhibition | |
| Thin Film | Monday Sessions |
| Session TF-MoA |
| Session: | Organic ALD |
| Presenter: | R.A. Hall, University of Colorado at Boulder |
| Authors: | R.A. Hall, University of Colorado at Boulder B. Yoon, University of Colorado at Boulder Y. Lee, University of Colorado at Boulder S.M. George, University of Colorado at Boulder |
| Correspondent: | Click to Email |
Molecular layer deposition (MLD) can be used to grow hybrid organic-inorganic films using organic MLD and inorganic ALD precursors. The alucones are the most studied of these hybrid organic-inorganic films. Alucone MLD depends on the sequential, self-limiting reactions between trimethylaluminum (TMA) and various organic alcohols. In this work, alucone MLD was performed using glycerol, a sugar alcohol with three hydroxyl groups or glycidol, an alcohol molecule that contains an epoxide group. Both of these alcohols should promote cross-linking in the alucone film for enhanced film stability and film toughness.
Studies of alucone MLD using TMA and glycerol (GL) or glycidol (GLY) were performed using in situ quartz crystal microbalance (QCM), Fourier transform infrared (FTIR) and quadrupole mass spectrometry (QMS) techniques. The FTIR studies showed that the TMA and GL or GLY reactions were both self-limiting. For the TMA + GL reaction, the FTIR spectra observed the growth/loss of AlCH3 and C-OH vibrations versus TMA/GL exposures. The mass gain measured by the QCM was 43 ng/cm2/cycle at 150ºC. QMS confirmed the presence of TMA and GL parents and observed the CH4 reaction products. Ex situ XRR measurements yielded a growth rate of 2.40 Å/cycle after 50 cycles at 150ºC.
Alucone films grown using TMA and GL or GLY were more stable than alucone films grown using TMA and ethylene glycol. The instability of alucone films has been attributed to unreacted AlCH3 species. To explore this issue, alucone films were grown using TMA, GL and H2O exposures in an ABC sequence. QCM measurements showed that the mass gain increased to 56 ng/cm2/cycle for this ABC sequence at 150°C. In addition, the QMS observed CH4 intensities during H2O exposures that were ~1/4 the intensity observed during GL exposures. These results indicate that H2O exposures can remove unreacted AlCH3 species and increase the mass gain per cycle.