Aluminum Nitride Micro-Channels Grown via Metal Organic Vapor Phase Epitaxy for MEMs Applications
Aluminum nitride (AlN) is a promising material for a number of applications due to its temperature and chemical stability. Furthermore, AlN maintains its piezoelectric properties at higher temperatures than more commonly used materials, such as Lead Zirconate Titanate (PZT) [1, 2], making AlN attractive for high temperature micro and nanoelectromechanical (MEMs and NEMs) applications including, but not limited to, high temperature sensors and actuators, micro-channels for fuel cell applications, and micromechanical resonators. This work presents a novel AlN micro-channel fabrication technique using Metal Organic Vapor Phase Epitaxy (MOVPE). AlN easily nucleates on dielectric surfaces due to the large sticking coefficient and short diffusion length of the aluminum species resulting in a high quality polycrystalline growth on typical mask materials, such as silicon dioxide and silicon nitride [3,4]. The fabrication process introduced involves partially masking a substrate with a silicon dioxide striped pattern and then growing AlN via MOVPE simultaneously on the dielectric mask and exposed substrate. A buffered oxide etch is then used to remove the underlying silicon dioxide and leave a free standing AlN micro-channel. The width of the channel has been varied from 5 ìm to 110 ìm and the height of the air gap from 130 nm to 800 nm indicating the stability of the structure. Furthermore, this versatile process has been performed on (111) silicon, c-plane sapphire, and gallium nitride epilayers on sapphire substrates. Reflection High Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM), and Raman measurements have been taken on channels grown on each substrate and indicate that the substrate is influencing the growth of the AlN micro-channels on the SiO2 sacrificial layer.
- Research Organization:
- West Virginia University, Morgantown, WV; National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR
- Sponsoring Organization:
- USDOE - Office of Fossil Energy (FE); AIXTRON; National Science Foundation (NSF); West Virginia University, Morgantown, WV
- DOE Contract Number:
- Not cited
- OSTI ID:
- 935157
- Report Number(s):
- DOE/NETL-IR-2008-057; NETL-TPR-2008; EPS 0554328; TRN: US200818%%595
- Resource Relation:
- Conference: 2007 Materials Research Society Fall Meeting, Boston, MA, November 26-30, 2007
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
ACTUATORS
ALUMINIUM
ATOMIC FORCE MICROSCOPY
DIELECTRIC MATERIALS
DIFFUSION LENGTH
ELECTRON DIFFRACTION
FABRICATION
FUEL CELLS
GALLIUM NITRIDES
NITRIDES
OXIDES
PZT
REFLECTION
RESONATORS
SAPPHIRE
SILICON
SILICON NITRIDES
STABILITY
SUBSTRATES
VAPOR PHASE EPITAXY