Strontium hafnate films are predicted to have desirable properties for use as a high-permittivity gate insulator. Such a film is of extreme interest to the scaling of Metal Oxide Semiconductor (MOS) transistors. Thin films of strontium hafnate have been prepared by cosputtering of Hf and SrO2. Strontium rich films appear to resist crystallization up to temperatures of 1000 °C, although high resolution electron microscopy suggests that nanocrystals form after high temperature annealing. Early measurements of MOS capacitors indicate a permittivity of approximately 35 and a lowest bandgap of about 4.4 eV.
Bibliographical noteFunding Information:
The authors wish to acknowledge the financial support of the Semiconductor Research Corporation and Sematech who sponsored this work through the Front End Processing Center. Part of the work was done at the Minnesota Nanofabrication Center and the Characterization Center, both of which receive partial support from NSF through the NNIN program.
- Metal-oxide Semiconductor Structure (MOS)