FERROELECTRIC MATERIAL FOR ULSI DEVICES

EXPLOITATION IN MICROELECTRONICS OF THE VERY HIGH DIELECTRIC CONSTANTS OF FERROELECTRIC PEROVSKITES SUCH AS BATIO3 AND PZT HAS BEEN LIMITED BY MATERIALS PROCESSING AND COMPATIABILITY PROBLEMS. HIGH QUALITY FERROELECTRIC THIN FILMS HAVE NOT BEEN GROWN AT TEMPERATURES COMPATIABLE WITH STANDARD SI OR GAAS PROCESSING TECHNOLOGIES. A HUGE PAYOFF AWAITS ONE WHO CAN UNLOCK THE POTENTIAL OF FERROELECTRIC PEROVSKITES FOR USE IN THE PRODUCTION OF LOW COST DRAMS. GROWTH TECHNIQUES COMPATIBLE WITH SILICON PROCESSING DEVELOPED AT ATM FOR THE HIGH TEMPERATURE SUPERCONDUCTORS WILL BE APPLIED TO THE DEPOSITION OF BA1-XSRXTIO3. BST HAS BEEN SELECTED FOR DEVELOPMENT FOR DRAM APPLICATIONS BECAUSE SYSTEMATIC VARIATION OF THE BA/SR RATIO OFFERS EXCELLENT CONTROL OVER THE MODULATION OF THE DIELECTRIC CONSTANT (500-1500) AND CONDUCTION PROPERTIES OF THE FERROELECTRIC FILMS. THE SPECIFIC GOAL OF THE PHASE I PROGRAM IS TO DEPOSIT ORIENTED BA1-XSRXTIO3 THIN FILMS ON SI(100) AT TEMPERATURES BELOW 650 DEGREES BY PE-MOCVD. A PROTOTYPE DRAM BASED ON BA1-XSRXTIO3 CAPACITOR STORAGE CELLS WILL BE FABRICATED AND TESTED IN PHASE II.