INTEGRATED MULTI-TRACK GMR READ/WRITE HEAD WIT CMOS-SOS CIRCUITRY

AN INTEGRATED MULTITRACK READ/WRITE HEAD AND ASSOCIATED CIRCUITRY SUITABLE FOR HIGH PERFORMANCE (100 MHZ), ULTRAHIGH DENSITY (2X10(9) BITS/IN(2)) RECORDING IS BEING DESIGNED. THE MAGNETORESISTIVE SENSOR USES GIANT MAGNETORESISTANCE RATIO (GMR) MATERIAL, WHICH PROVIDES A MUCH HIGHER SIGNAL (ABOUT TEN TIMES) COMPARED WITH STANDARD MATERIALS BECAUSE OF HIGHER MAGNETORESISTANCE AND HIGHER SHEET RESISTIVITY. THE ORIENTATION OF THE SENSOR WILL BE ORTHOGONAL TO THE ORIENTATION OF THE SENSORS IN USE TODAY FOR IMPROVED RELIABILITY AND HIGHER DENSITY. THE ASSOCIATED CIRCUITRY IS BEING DESIGNED USING CMOS ON A SUBSTRATE OF SILICON ON SAPPHIRE (SOS) WHICH HAS BOTH FAVORABLE WEAR CAPABILITY AND LOWER PARASITIC CAPACITANCES THAN SILICON, AND HENCE WILL IMPROVE THE ELECTRICAL PERFORMANCE OF THE ON-CHIP CIRCUITRY. SENSORS FOR SERVO TRACKS ARE INCLUDED IN THE DESIGN. THE HEAD WILL BE DESIGNED, AND SATISFACTORY GMR MATERIALS WILL BE DEMONSTRATED ON A SUBSTRATE COMPRISED OF PERMALLOY SHIELDING MATERIAL ON SOS.