ROOM-TEMPERATURE - OPERATING SPIN-VALVE TRANSISTORS FORMED BY VACUUM BONDING

Functional integration between semiconductors and ferromagnets was dem onstrated with the spin-valve transistor. A ferromagnetic multilayer w as sandwiched between two device-quality silicon substrates by means o f vacuum bonding. The emitter Schottky barrier injected hot electrons into the spin-valve base. The collector Schottky barrier accepts only ballistic electrons, which makes the collector current very sensitive to magnetic fields. Room temperature operation was accomplished by pre paring Si-Pt-Co-Cu-Co-Si devices. The vacuum bonding technique allows the realization of many ideas for vertical transport devices and forms a permanent link that is useful in demanding adhesion applications.