Preparation and some magnetic properties of amorphous rare earth-transition metal films with perpendicular anistropy for bubble memories T. KATAYAMA MicroelectronicsJ. 12 (5), 23 (1981) A preparation method for amorphous R-T flms for magnetic bubbles is described. Positive Ku is induced by a resputtering effect in amorphous Gd-Co and Gd-Co- Mo films. However, sputtering without resputtering effect and evaporation produce positive Ku in amor- phous R-T films such as Gd-Fe, Tb-Fe, Dy-Fe and so on. Some magnetic properties of amorphous R-T films are also described. The addition of Mo improves the chemical and thermal stabilities of films and it reduces a positive Ku and T¢. Annealing reduces positive Ku, but enhances 4TMs, T¢ and exchange stiffness constant A.

C-MOS PROM density hits 16-K JAMES B. BRINTON Electronics 193 ( 25 August 1981) Polysilicon-fuse programmable read-only memories operate on 25m W/MHz, typically, and stand by on 500 ttW.

High frequency magnetic bubble devices D. J. BREED and A. G. H. VERHULST MicroelectronicsJ. 12 (5) (1981) In connection with data rate and energy dissipation in a magnetic bubble device the dynamic properties of magnetic bubble films, such as the domain wall mobility and the maximum domain waU velocity are important parameters. At present, the standard magnetic bubble device is the field access device. In this device the bubbles are propagated by changing magnetic gradient fields arising from a NiFe circuit applied to the bubble film. The NiFe pattem is magnetised by a rotating field in the plane of the film. Due to the dissipation in the coils for the rotating in-plane field, the frequency is limited to about 300 kHz. The dynamic properties of the present bubble device materials, which are iron garnets with a strong uniaxial anisotropy, are sufficient for this frequency. A promising approach for future devices is current access propagation. In that case bubbles are propagated by changing magnetic gradient fields which are present below a current conductor circuit driven by alternating currents. The maximum frequency can then be much higher but an increase of the maximum bubble velocity is then neces- sary. In these devices heat generation takes place directly on the bubble chip in the conductor circuit. Therefore the mobility, which directly sets the value of the drive current, should be sufficiently high.

Preparation and some magnetic properties of amorphous rare earth-transition metal films with perpendicular anistropy for bubble memory T. KATAYAMA MicroelectronicsJ. 12 (5) (1981) Crystalline magnetic garnet films prepared by liquid phase epitaxy (LPE) provide excellent properties for magnetic bubble memories. On the other hand, it has been reported also that some films of-a~norphous rare earth-transition metal (R-T) alloys are feasible for bubble materials, where R = heavy rare earth elements such as Gd, Tb, Dy, Ho, Er; T = Fe, Co, Ni. The amorphous R-T films such as Gd-Co, Gd-Co-Mo, Gd- Fe have a number of advantages and disadvantages

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compared with the crystalline garnets. A wider range of magnetic properties and less expense in preparation are the points of advantage. Electrical conductivity and instability of the physical properties due to the amor- phous structure are disadvantages. The basic require- ments of amorphous films for the bubble materials are almost the same as those of garnet. The development of amorphous magnetic bubble memory chips has been carried out by several workers. Kryder et al have succeeded in fabricating a bubble memory chip of 8 kbit capacity using an amorphous Gd-Co-Mo film, and have succeeded also in high speed operation up to 1 MHz. Subsequently, investigations on amorphous bubble memory chips would seem to have slowed because LPE garnet films with submicron bubbles have been developed. Nevertheless, the amorphous R-T films are now studied intensively from both practical and physical points of view. In this paper, the preparation and some magnetic properties of amorphous R-T films for bubble are briefly described.

3. Hybrids Electroless nickel resistors formed on IMST substrate NORIO MIURA, YOSHIO FUURA and AKIRA KAZAMI IEEE Trans. Components Hybrids Mfg Technol. cm~rr-4 (4), 532 (1981) Ni-P alloy resistors electrolessly plated on a unique insulated metal substrate technology (IMST) substrate are described. The construction of the IMST substrate with electroless nickel resistors is presented. The resistor fabrication processes are shown. The obtained practical sheet resistivity of electrodeless nickel resistors was 0.5-20ft/1:]. Laser trimming was utilised to produce resistors with a tolerance of ---0.1 percent; and a resistance range from 0.111 to 100 kfl. The thermal coefficient of resistance (TCR) was closely related to the phosphorus content. A TCR of +80 ppmrC minimum was obtained. The electroless nickel resistors exhibited excellent stability in various life and high power dis- sipation tests. Applications to audio power hybrid integrated circuits (ICs) and resistor arrays are shown.

Thick film circuits: present state and future development J. NOVOTNY Electrocomponent Sci. Technol. 9, 131 (1981) Thick film technology has been known for about 20 years. The technique of inks, printing, firing and trimming has grown in this time to a well established state-of-the-art. This paper gives an overview of the status today and an outlook into the future, not only for thick film, but also for hybrids built out of thick film circuits with incorporation of additional components. The paper gives the main market figures and market segments for thick film applications and mentions the main reasons for this. New fields of applications for thick film will be found in the future where considerations like reliability, space savings and cost advantage are of importance.

A moisture protection screening test for hybrid circuit encapsulants R. G. MANCKE IEEE Trans. Components Hybrids Mfg Technol. CHMT-4 (4), 492 (1981) An empirical comparative screening test for polymeric encapsulants reported here has been used to indicate