Single Crystal Diamond Films
Diamond has impressive qualities that make it an ideal material for a number
of applications. A few of its properties are:
However in order to take advantage of most of these properties, it is necessary
to grow diamond much as we can other coating materials and semiconductors
- as a thin film deposited on another material, or as a single crystal "window"
or wafer (like silicon). This is where the trouble starts. In part, because
of its superior properties, diamond is notoriously difficult to grow
on anything but another diamond.
Our Research
We are presently examining different substrates for single crystal diamond
deposition. In recent years some success in growing heteroepitaxial diamond
on iridium thin films has been reported by groups in Japan and Germany . Iridium
films have been deposited by sputtering onto magnesium oxide in Japan, and
by e-beam evaporation onto strontium titanate in Germany. These are then used as substrates
for diamond growth using chemical vapor deposition.
We are depositing single crystal (100) iridium via UHV electron beam deposition
onto a number of different substrates including magnesium oxide, strontium
titanate, lanthanum aluminate and most recently sapphire.
We use a microwave plasma chemical vapor depostion chamber with methane
and hydrogen feed gases to deposit the diamond films. A negative bias to the substrate
bias enhances the diamond growth. Part of my doctoral thesis
work has been to modify the system for bias enhanced experiments.