International Business Machines Corporation

Amitava Gangulee

Jerome J Cuomo

James K Howard

Paul S Ho

Praveen Chaudhari

Robert J Miller

Joseph Adam Aboaf

Francois M d'Heurle

Robert J Kobliska

John Kobliska

A laminated conductor includes a lower thin film of nickel deposited upon a substrate containing silicon. Upon the film of nickel, a thicker film of gold is deposited as the conductive portion of the conductor. On the upper surface of the gold layer is deposited a thin film of nickel. Failure of the conductor because of electromigration is reduced dramatically as compared with use of molybdenum instead of nickel in the laminated structure.

Nickel-gold-nickel conductors for solid state devices

A sputtered thin film of an amorphous material composed of a magnetic transition metal X and element Y plus possibly an element Z has low coercivity for domains in the plane, has a well defined and stable magnetic easy axis which is extremely stable without heating above the Curie point, with a high and flat value of permeability from low frequencies to greater than 10 megahertz. Metal X can include at least one of Fe, Ni, and Co. Element Y can include at least one of Si and B. Element Z can be included composed of Cr, for example.

Amorphous magnetic thin films with highly stable easy axis

These amorphous metal-alloy films include nitrogen, greater than about one atomic percent at least one transition metal selected from Cr, Fe, Co and Ni with at least one element forming an amorphous alloy therewith, selected from the 'glass forming' elements, i.e., B, Si, Al, C and P. The alloys can be formed by deposition in a vacuum chamber. When films are sputtered, the target is composed of the above alloy elements with at least one element selected from each of the transition metal and glass forming element groups. Sputtering occurs in an atmosphere above about 2% vol. N.sub.2 gas mixed with an inert gas, e.g., Ar. Alloys produced include N, i.e., (Co-Fe-B)N and (Fe-B)N. Above about 2 atomic % N in the film, films have lower values of saturation magnetization 4.pi.M.sub.s. Above a 2% vol. N.sub.2 gas in the plasma, electrical resistivity increases. Over 0.5% vol. N.sub.2 gas in the plasma, the film's effective perpendicular anisotropy field H.sub.k.sup.* increases. For (Co-Fe-B)N, the anisotropy direction moves from in plane to perpendicular above 2% vol. N.sub.2 plasmas. For (Fe-B)N, H.sub.k.sup.* increases with N.sub.2 up to 10% vol. N.sub.2 plasma. The N% in a film varies linearly with the log of N.sub.2 % vol. Films show markedly improved adhesion, corrosion resistance and hardness. Magnetic thermal stability increases with N.sub.2 above about 5% vol. N.sub.2 in a plasma. Structural and magnetic properties are stable for annealing up to 400.degree. C.

Amorphous metallic and nitrogen containing alloy films

A method and resulting structure for forming narrow intermetallic stripes which will carry high currents on bodies such as semiconductors, integrated circuits, and magnetic bubble structures, is set forth. The conductive stripe includes gold with at least one transition metal from the group niobium, zirconium and hafnium. The gold and at least one transition metal are deposited onto a supporting body. The deposited metallic material is then annealed at a temperature between about 200.degree. C. and 500.degree. C. for a time sufficient to form a gold-transition metal compound within a gold matrix. The conductive stripes are formed by masking and removing portions of the annealed metallic material to produce conductive stripes which may have a width of 6.times.10.sup.-4 inches or less. These stripes have significantly improved electromigration performance and do not have significantly increased resistance.

Electromigration resistance in gold thin film conductors

In accordance with the disclosure, certain impurities, e.g., alloying additions, are introduced in thin metal film to negate the driving force or the effect of the driving force which causes the hillock formation. Such thin metallic films are usually fabricated on the substrates which have different thermal coefficients of expansion than the film itself, and during thermal cycling stresses can be introduced into the film. This stress may serve as a driving force for atom movement and, therefore, to the formation of hillocks. The vehicle by which the induced stress in a film effects the requisite atom movement is via defect movement, and when the force is compressive this gives rise to hillocks. In the practice of this disclosure, impurity additions introduced into a film affect hillock growth by their interaction with the defects which give rise to the requisite atom movement. Systematically selected impurity additions are introduced into a film during fabrication thereof which inhibit the defect movement in the class consisting of a migration of point defects, linear defects and planar defects wherein the linear defects are dislocations and the planar defects are grain boundaries. Usually, the addition of impurities into a metal film is termed alloying and the resultant film is termed an alloyed film. The alloying addition may be either soluble or insoluble in the film. This will determine the choice of possible modes of fabrication. When the alloy addition is soluble, it is included within the limits of solubility at the temperature at which it is introduced. When the alloy addition is insoluble, it is introduced during fabrication and quantity thereof may be significantly better than the quantity capable of being sustained were the alloying addition and the film to be in thermal equilibrium.

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Croton-on-Hudson, NY, United States of America

Amitava Gangulee