ORNL Develops &nCrystaline Oxide
Staff -- Semiconductor International, 6/1/1999
Researchers
at Oak Ridge National Laboratory (ORNL, Oak Ridge, Tenn.) have demonstrated
the viability of crystalline oxides for field effect transistor gates. The results
of the research address the shortcomings of ultrathin amorphous silicon dioxide
layers.
Research team leader Rodney McKee said, "Silicon dioxide layers of less than about three nm become less efficient because they lose charge due to quantum mechanical tunneling. So the challenge was to come up with a structure that has the physical thickness to support the electric field yet stores the electrical charge more effectively."
The ORNL team used molecular beam epitaxy (MBE) to build the interface between silicon and the oxide. "As a result, we can maintain perfect registry between the two materials and obtain the desired crystalline interface," McKee said. More work remains before the process can be adopted by semiconductor manufacturers.
Funding for the project has been provided by the Department of Energy and
ORNL's Laboratory Directed Research and Development Program. 
