Roger A. Miller

Substrates for magnetic hard disks for gigabit recording

The objective of head-disk designers has been-and will continue to be-to increase areal density, volumetric density and ruggedness and to provide improved performance and reliability of hard disk drives. One of the keys to this effort is the substrate which significantly affects flyability and reliability characteristics of the disk and greatly impacts the performance of the magnetic films. This paper explores the substrate properties which most affect performance and compares various substrates in terms of these properties.

Materials and Processes For Silicon TFT's On Aluminosilicate Glass: An Alternative Soi Technology

As-deposited polycrystalline silicon and argon ion laser recrystallized silicon thin film transistors (TFTs) have been fabricated on Corning Code 1729 glass substrates. This novel aluminosilicate glass has an expansion coefficient matched to that of silicon and a chemical durability comparable to that of fused silica. N-channel enhancement mode transistors were made using conventional IC device fabrication procedures (including thermal oxidation to form the gate insulator) modified to have a maximum processing temperature of 800 C. The- polycrystalline silicon TFTs exhibit leakage currents of less than 2x10 -11 A/ μm; of channel width and good stability and reproducibility. Transistors made in the recrystallized silicon show field effect electron mobilities as high as 270 cm 2 /V s, approximately 15 times the mobility of comparable devices made in as-deposited polycrystalline silicon. The recrystallized silicon devices also exhibit lower threshold voltages and lower leakage currents than do the comparable polycrystalline silicon devices. Major advantages of this TFT technology include the use of a novel, potentially low cost glass substrate and the simultaneous processing of both polycrystalline and recrystallized silicon devices on the same substrate material. This approach represents a new avenue for the incorporation of active devices into a variety of applications including integrated active matrix displays.