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Fabrication of Sputtered Thin Film Magnetic Memory Planes

IP.com Disclosure Number: IPCOM000095540D
Original Publication Date: 1964-Feb-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Kay, E: AUTHOR

Abstract

High speed magnetic memory planes can be fabricated on metal. Such is effected by first sputtering onto such metal substrates a non-magnetic layer. This layer provides the required smooth surface characteristics and also serves as a diffusion barrier between the metal and the magnetic film which is subsequently deposited by sputtering. Thus, fabrication of both substrate layer and magnetic layer in the same sputtering apparatus is permitted. This intermediate layer must have the following properties to be suitable: 1. Be thick enough to completely smooth out any undesirable surface topography on the polished metal substrate, 2. Have no inherent structure of its own, i. e., must be nongranular, 3. Be non-magnetic, 4. Be chemically stable at temperatures up to 450 degrees C., 5.

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Fabrication of Sputtered Thin Film Magnetic Memory Planes

High speed magnetic memory planes can be fabricated on metal. Such is effected by first sputtering onto such metal substrates a non-magnetic layer. This layer provides the required smooth surface characteristics and also serves as a diffusion barrier between the metal and the magnetic film which is subsequently deposited by sputtering. Thus, fabrication of both substrate layer and magnetic layer in the same sputtering apparatus is permitted. This intermediate layer must have the following properties to be suitable: 1. Be thick enough to completely smooth out any undesirable surface topography on the polished metal substrate, 2. Have no inherent structure of its own, i. e., must be nongranular, 3. Be non-magnetic, 4. Be chemically stable at temperatures up to 450 degrees C., 5. Must not alloy or be miscible in any way with the magnetic film which is subsequently deposited onto this film in a plasma environment, 6. Must be transportable from source to substrate at high rates.

By using very refractory materials, such as tantalum, niobium, or molybdenum, all of the above requirements can be met and a suitable film can be formed if the following conditions are maintained: 1. The sputtering deposition rate is kept high, such as at 15 - 20 angstroms per second to produce a maximum number of nucleating sites. 2. A high inert gas pressure is maintained in the discharge so that the sputtered particles are thoroughly...