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MIT Electrical Engineering and Computer Science
EECS Event |
Tuesday, February 27, 2001
4:00 PM (reception 3:30)
Edgerton Hall, Room 34-101
MTL VLSI Seminar
Abstract
The storage density in magnetic recording disk drives has increased annually by 60% to 100% for the last 10 years. Specifically, today’s hard disk drive products have areal densities of 17 Gibt/in2 at costs of $5.00 / GB. One component of the magnetic recording system is the thin film transducer, i.e. the magnetic thin film head, which writes or orients regions of magnetization on the recording disk and which reads or senses magnetic fields from these magnetized regions. The magnetized regions on the disk are the bit cells. The lithographically defined dimensions of a single thin film head determine the bit cell dimensions on an entire disk surface. No thin film processing on the disk surface is required.
This seminar will discuss the physics, processing technology, and scaling issues for thin film recording heads. Recording physics will be introduced to describe the read and write process in magnetic recording. Processing technology will address the similarities and differences of thin film head fabrication and integrated circuit fabrication. Most important, scaling issues will describe future requirements for thin film heads driven by the magnetic recording industry’s version of Moore’s Law. One scaling issue is that any doubling of areal density requires a 30% reduction in the minimum feature of the head transducer. Integrated circuit features decrease by 10% each year. A second scaling issue relates to output signals from the thin film head. Any reduction in sensor lateral dimension will reduce output sensitivity unless materials, which detect magnetic fields, magnetoresistive (MR) materials, can be configured with higher MR coefficients. Here are specifics. Present thin film heads have minimum features of 0.4 um, MR coefficients of 10%, and areal densities of 17 Gibit/in2. Within 5 years, thin film heads will require minimum features less than 0.1 um, MR following web site: (http://www.almaden.ibm.com/sst/).