Ultrathin diamondlike carbon films deposited by filtered carbon vacuum arcs

Abstract

This work was supported through the CRADA BG98-084 (01) ABSTRACTUltrathin (< 5 nm) hard carbon films are of great interest to the magnetic storage industry as the areal density approaches 100 Gbit/in 2 . These films are used as overcoats to protect the magnetic layers on disk media and the active elements of the read-write slider. Tetrahedral amorphous carbon films can be produced by filtered cathodic arc deposition, but the films will only be accepted by the storage industry only if the "macroparticle" issue has been solved. Better plasma filters have been developed over recent years. Emphasis is put on the promising twist filter system -a compact, open structure that operates with pulsed arcs and high magnetic field. Based on corrosion tests it is shown that the macroparticle reduction by the twist filter is satisfactory for this demanding application, while plasma throughput is very high. Ultrathin hard carbon films have been synthesized using Sfilter and twist filter systems. Film properties such as hardness, elastic modulus, wear, and corrosion resistance have been tested. Index Terms: diamond-like carbon, cathodic vacuum arc, macroparticle filtering, magnetic storage, carbon overcoats 3 I. INTRODUCTIONUltrathin (< 5 nm) hard carbon films are used as protective overcoats on hard disks and readwrite heads. The tribological properties of the head-disk interface are not only of mechanical but also of chemical nature: the overcoat should protect the magnetic layers against wear and corrosion [1, 2]. The areal density of information stored in disk drive products increased at an amazing rate of over 65% for many years rate, and continues to accelerate to even greater rates [3]. To accomplish this, the "magnetic spacing" between the magnetic layers of the disk and read/write sensor of the head must continue to decrease. The magnetic spacing includes the overcoats, lubrication, and the fly height. Thinner overcoats allow the read-write head to be closer to the magnetic layer of the disk, and hence, the size of individual bits on the disk to be smaller. As we work toward an areal density of 100 Gbit/in

Deposition Technologies

“…They have been serving as wear and corrosion protection with excellent tribological properties and proved to be superior to DLC films deposited by alternative technologies [75,76]. DLC by now is widely used for micro and nanotribological purposes in various applications.…”

Some Applications of Cathodic Arc Coatings

“…The issues of overcoats, including filtered-arc-deposited ta-C, have been discussed in a number of papers and reviews [63,64,65,66,67,68,69]. A significant contribution to the industry's success was the reduction of overcoat thickness down to about 2 nm, with current attempts to reduce this even further.…”

“…Therefore, for most of the last two decades, the industry preferred sputtering and later ion beam technology to fabricate ultrathin protective films. In recent years, however, the requirements led to the development of improved filter schemes, which are characterized by filter bending angles greater than 908 ( [65,68,70,71,72,73], see Chapter 7).…”

Synthesis of Ultrathin Ta-C Films by Twist-Filtered Cathodic Arc Carbon Plasmas

“…Preliminary measurements of ultrathin films obtained by using a prototype S-filter and Twist Filter have been reported elsewhere [36,37]. Two major steps were done recently: one was the development of an alpha-version Twist Filter system, and the other was its installation in a class 100 cleanroom at Read-Rite corporation.…”