The spin-valve transistor: technologies and progress

The paper describes the necessary technologies needed for realising a RT op erating spin-valve transistor (SVT) which is in fact a magnetic controlled metal base transistor. The preparation of a 350 x 350 mu m(2) SVT consistin g of an Si emitter and collector and Co/Cu/Co GMR multilayer are described. The metal bonding technology in vacuum is described, which is essential fo r preparing small SVTs with photolithography and etching technologies. The quality of the bonding interfaces as well as the interface between GMR laye r and semiconductor are important for the electrical properties. In more ge neral terms the SVT research also establishes the feasibility of various hy brid structures combining semiconductor technology and spin electronics. (C ) 1999 Elsevier Science B.V. All rights reserved.