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The Head-Disk Interface Roadmap to an Areal Density of Tbit/in 2

DOI: 10.1155/2013/521086

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This paper reviews the state of the head-disk interface (HDI) technology, and more particularly the head-medium spacing (HMS), for today’s and future hard-disk drives. Current storage areal density on a disk surface is fast approaching the one terabit per square inch mark, although the compound annual growth rate has reduced considerably from ~100%/annum in the late 1990s to 20–30% today. This rate is now lower than the historical, Moore’s law equivalent of ~40%/annum. A necessary enabler to a high areal density is the HMS, or the distance from the bottom of the read sensor on the flying head to the top of the magnetic medium on the rotating disk. This paper describes the various components of the HMS and various scenarios and challenges on how to achieve a goal of 4.0–4.5?nm for the 4?Tbit/in2 density point. Special considerations will also be given to the implication of disruptive technologies such as sealing the drive in an inert atmosphere and novel recording schemes such as bit patterned media and heat assisted magnetic recording. 1. Introduction As the areal density of commercial hard disk drives is quickly approaching the terabit per square inch milestone [1–5] (Figure 1), the need to improve the reliability of the head-disk interface (HDI) and to further decrease the head-medium spacing (HMS) is becoming eversmore critical [3, 6, 7]. Low HMS is a necessary enabler to good writability as well as strong read-back signal integrity [8, 9]. It is estimated that the HMS will soon need to cross the 7?nm mark in order to reach this terabit per square inch density point [2, 6]. It is remarkable to realize that the error rate of the stored digital signal that is being read back improves approximately by about 2x for every 0.3–0.5 nanometer of decreased HMS. In addition to relentless demand for novel, ultrathin protecting films of overcoat and lubricant, and subnanometer air gap between the disk and the head, alternative recording technologies presently being contemplated involve heating the disk to over 500°C (heat-assisted magnetic recording or HAMR) [10–12] and/or physically isolating magnetic bits on small islands of sub-30?nm in physical dimensions (bit-patterned recording or BPR) [13–16]. Figure 1: Areal density evolution of HDD and flash memory. After Grochowski [ 17], with permission. In this paper, the roadmap to an areal density of 4 terabits per square inches will be discussed. Particular emphasis will be given to the various spacing components that comprise the HMS budgetand their physical limits. The various implications of recording

References

[1]  R. W. Wood, J. Miles, and T. Olson, “Recording technologies for terabit per square inch systems,” IEEE Transactions on Magnetics, vol. 38, no. 4, pp. 1711–1718, 2002.
[2]  R. Wood, “The feasibility of magnetic recording at 1 Terabit per square inch,” IEEE Transactions on Magnetics, vol. 36, no. 1, pp. 36–42, 2000.
[3]  C. M. Mate, Q. Dai, R. N. Payne, B. E. Knigge, and P. Baumgart, “Will the numbers add up for sub-7-nm magnetic spacings? Future metrology issues for disk drive lubricants, overcoats, and topographies,” IEEE Transactions on Magnetics, vol. 41, no. 2, pp. 626–631, 2005.
[4]  M. E. Schabes, “Micromagnetic simulations for terabit/in2 head/media systems,” Journal of Magnetism and Magnetic Materials, vol. 320, no. 22, pp. 2880–2884, 2008.
[5]  M. Mallary, A. Torabi, and M. Benakli, “One terabit per square inch perpendicular recording conceptual design,” IEEE Transactions on Magnetics, vol. 38, no. 4, pp. 1719–1724, 2002.
[6]  B. Marchon and T. Olson, “Magnetic spacing trends: from LMR to PMR and beyond,” IEEE Transactions on Magnetics, vol. 45, no. 10, pp. 3608–3611, 2009.
[7]  J. Gui, “Tribology challenges for head-disk interface toward 1 Tb/in2,” IEEE Transactions on Magnetics, vol. 39, no. 2, pp. 716–721, 2003.
[8]  R. L. Wallace, “The reproduction of magnetically recorded signals,” Bell System Technical Journal, vol. 30, pp. 1145–1173, 1951.
[9]  B. Marchon, K. Saito, B. Wilson, and R. Wood, “The limits of the Wallace approximation for PMR recording at high areal density,” IEEE Transactions on Magnetics, vol. 47, pp. 3422–3425, 2012.
[10]  M. H. Kryder, E. C. Gage, T. W. Mcdaniel et al., “Heat assisted magnetic recording,” Proceedings of the IEEE, vol. 96, no. 11, pp. 1810–1835, 2008.
[11]  B. C. Stipe, T. C. Strand, C. C. Poon et al., “Magnetic recording at 1.5?Pbm-2 using an integrated plasmonic antenna,” Nature Photonics, vol. 4, no. 7, pp. 484–488, 2010.
[12]  W. A. Challener, C. Peng, A. V. Itagi et al., “Heat-assisted magnetic recording by a near-field transducer with efficient optical energy transfer,” Nature Photonics, vol. 3, pp. 220–224, 2009.
[13]  E. A. Dobisz, Z. Z. Bandi?, T. W. Wu, and T. Albrecht, “Patterned media: nanofabrication challenges of future disk drives,” Proceedings of the IEEE, vol. 96, no. 11, pp. 1836–1846, 2008.
[14]  B. D. Terris, T. Thomson, and G. Hu, “Patterned media for future magnetic data storage,” Microsystem Technologies, vol. 13, no. 2, pp. 189–196, 2007.
[15]  X. Yang, S. Xiao, W. Wu et al., “Challenges in 1 Teradotin. 2 dot patterning using electron beam lithography for bit-patterned media,” Journal of Vacuum Science & Technology B, vol. 25, no. 6, pp. 2202–2209, 2007.
[16]  A. Kikitsu, “Prospects for bit patterned media for high-density magnetic recording,” Journal of Magnetism and Magnetic Materials, vol. 321, no. 6, pp. 526–530, 2009.
[17]  E. Grochowski, Future Technology Challenges for NAND Flash and HDD Products, Flash Memory Summit, 2012.
[18]  S. I. Iwasaki, “Principal complementarity between perpendicular and longitudinal magnetic recording,” Journal of Magnetism and Magnetic Materials, vol. 287, pp. 9–15, 2005.
[19]  M. Suk, K. Miyake, M. Kurita, H. Tanaka, S. Saegusa, and N. Robertson, “Verification of thermally induced nanometer actuation of magnetic recording transducer to overcome mechanical and magnetic spacing challenges,” IEEE Transactions on Magnetics, vol. 41, no. 11, pp. 4350–4352, 2005.
[20]  K. Miyake, T. Shiramatsu, M. Kurita, H. Tanaka, M. Suk, and S. Saegusa, “Optimized design of heaters for flying height adjustment to preserve performance and reliability,” IEEE Transactions on Magnetics, vol. 43, no. 6, pp. 2235–2237, 2007.
[21]  T. Shiramatsu, M. Kurita, K. Miyake, et al., “Drive-integration of active flying-height control slider with micro thermal actuator,” IEEE Transactions on Magnetics, vol. 42, no. 10, pp. 2513–2515, 2006.
[22]  J. Itoh, Y. Sasaki, K. Higashi, H. Takami, and T. Shikanai, “An experimental investigation for continuous contact recording technology,” IEEE Transactions on Magnetics, vol. 37, no. 4, pp. 1806–1808, 2001.
[23]  C. M. Mate, P. C. Arnett, P. Baumgart et al., “Dynamics of contacting head-disk interfaces,” IEEE Transactions on Magnetics, vol. 40, no. 4, pp. 3156–3158, 2004.
[24]  S. C. Lee and A. A. Polycarpou, “Microtribodynamics of pseudo-contacting head-disk interfaces intended for 1 Tbit/in2,” IEEE Transactions on Magnetics, vol. 41, no. 2, pp. 812–818, 2005.
[25]  B. Liu, M. S. Zhang, S. K. Yu et al., “Towards fly- and lubricant-contact recording,” Journal of Magnetism and Magnetic Materials, vol. 320, no. 22, pp. 3183–3188, 2008.
[26]  B. Liu, M. S. Zhang, S. K. Yu et al., “Lube-surfing recording and its feasibility exploration,” IEEE Transactions on Magnetics, vol. 45, no. 2, pp. 899–904, 2009.
[27]  W. Hua, B. Liu, S. K. Yu, and W. D. Zhou, “Contact recording review,” Microsystem Technologies-Micro-and Nanosystems-Information Storage and Processing Systems, vol. 16, pp. 493–503, 2010.
[28]  L. Wu and F. E. Talke, “Modeling laser induced lubricant depletion in heat-assisted-magnetic recording systems using a multiple-layered disk structure,” Microsystem Technologies, vol. 17, no. 5-7, pp. 1109–1114, 2011.
[29]  Y. S. Ma, L. Gonzaga, C. W. An, and B. Liu, “Effect of laser heating duration on lubricant depletion in heat assisted magnetic recording,” IEEE Transactions on Magnetics, vol. 47, no. 10, pp. 3445–3448, 2011.
[30]  W. D. Zhou, Y. Zeng, B. Liu, S. K. Yu, W. Hua, and X. Y. Huang, “Evaporation of polydisperse perfluoropolyether lubricants in heat-assisted magnetic recording,” Applied Physics Express, vol. 4, no. 9, Article ID 095201, 3 pages, 2011.
[31]  L. Wu, “Lubricant distribution and its effect on slider air bearing performance over bit patterned media disk of disk drives,” Journal of Applied Physics, vol. 109, no. 7, Article ID 074511, 2011.
[32]  B. E. Knigge, Z. Z. Bandic, and D. Kercher, “Flying characteristics on discrete track and bit-patterned media with a thermal protrusion slider,” IEEE Transactions on Magnetics, vol. 44, no. 11, pp. 3656–3662, 2008.
[33]  S. Shen, B. Liu, S. Yu, and H. Du, “Mechanical performance study of pattern media-based head-disk systems,” IEEE Transactions on Magnetics, vol. 45, no. 11, pp. 5002–5005, 2009.
[34]  L. Li and D. B. Bogy, “Dynamics of air bearing sliders flying on partially planarized bit patterned media in hard disk drives,” Microsystem Technologies, vol. 17, no. 5–7, pp. 805–812, 2011.
[35]  W. D. Zhou, B. Liu, S. K. Yu, and W. Hua, “Inert gas filled head-disk interface for future extremely high density magnetic recording,” Tribology Letters, vol. 33, no. 3, pp. 179–186, 2009.
[36]  J. Robertson, “Requirements of ultrathin carbon coatings for magnetic storage technology,” Tribology International, vol. 36, no. 4–6, pp. 405–415, 2003.
[37]  X. Shi, Y. H. Hu, and L. Hu, “Tetrahedral amorphous carbon (ta-C) ultra thin films for slider overcoat application,” International Journal of Modern Physics B, vol. 16, no. 6-7, pp. 963–967, 2002.
[38]  G. G. Wang, X. P. Kuang, H. Y. Zhang, et al., “Silicon nitride gradient film as the underlayer of ultra-thin tetrahedral amorphous carbon overcoat for magnetic recording slider,” Materials Chemistry and Physics, vol. 131, pp. 127–131, 2011.
[39]  N. Yasui, H. Inaba, K. Furusawa, M. Saito, and N. Ohtake, “Characterization of head overcoat for 1 Tb/in2 magnetic recording,” IEEE Transactions on Magnetics, vol. 45, no. 2, pp. 805–809, 2009.
[40]  J. Robertson, “Ultrathin carbon coatings for magnetic storage technology,” Thin Solid Films, vol. 383, no. 1-2, pp. 81–88, 2001.
[41]  T. Yamamoto and H. Hyodo, “Amorphous carbon overcoat for thin-film disk,” Tribology International, vol. 36, no. 4–6, pp. 483–487, 2003.
[42]  C. Y. Chan, K. H. Lai, M. K. Fung, et al., “Deposition and properties of tetrahedral amorphous carbon films prepared on magnetic hard disks,” Journal of Vacuum Science & Technology A, vol. 19, pp. 1606–1610, 2001.
[43]  B. K. Yen, R. L. White, R. J. Waltman, C. Mathew Mate, Y. Sonobe, and B. Marchon, “Coverage and properties of a-SiNx hard disk overcoat,” Journal of Applied Physics, vol. 93, no. 10, pp. 8704–8706, 2003.
[44]  Y. Hijazi, E. B. Svedberg, T. Heinrich, and S. Khizroev, “Comparative corrosion study of binary oxide and nitride overcoats using in-situ fluid-cell AFM,” Materials Characterization, vol. 62, no. 1, pp. 76–80, 2011.
[45]  E. B. Svedberg and N. Shukla, “Adsorption of water on lubricated and non lubricated TiC surfaces for data storage applications,” Tribology Letters, vol. 17, no. 4, pp. 947–951, 2004.
[46]  F. Rose, B. Marchon, V. Rawat, D. Pocker, Q. F. Xiao, and T. Iwasaki, “Ultrathin TiSiN overcoat protection layer for magnetic media,” Journal of Vacuum Science & Technology A, vol. 29, Article ID 051502, 11 pages, 2011.
[47]  M. L. Wu, J. D. Kiely, T. Klemmer, Y. T. Hsia, and K. Howard, “Process-property relationship of boron carbide thin films by magnetron sputtering,” Thin Solid Films, vol. 449, no. 1-2, pp. 120–124, 2004.
[48]  M. A. Samad, E. Rismani, H. Yang, S. K. Sinha, and C. S. Bhatia, “Overcoat free magnetic media for lower magnetic spacing and improved tribological properties for higher areal densities,” Tribology Letters, vol. 43, pp. 247–256, 2011.
[49]  E. Rismani, S. K. Sinha, H. Yang, and C. S. Bhatia, “Effect of pretreatment of Si interlayer by energetic C+ ions on the improved nanotribological properties of magnetic head overcoat,” Journal of Applied Physics, vol. 111, Article ID 084902, 10 pages, 2012.
[50]  X. C. Guo, B. Knigge, B. Marchon, R. J. Waltman, M. Carter, and J. Burns, “Multidentate functionalized lubricant for ultralow head/disk spacing in a disk drive,” Journal of Applied Physics, vol. 100, no. 4, Article ID 044306, 2006.
[51]  X. C. Guo, B. Marchon, R. H. Wang, et al., “A multidentate lubricant for use in hard disk drives at sub-nanometer thickness,” Journal of Applied Physics, vol. 111, Article ID 024503, 7 pages, 2012.
[52]  D. Gonzalez, V. Nayak, B. Marchon, R. Payne, D. Crump, and P. Dennig, “The dynamic coupling of the slider to the disk surface and its relevance to take-off height,” IEEE Transactions on Magnetics, vol. 37, no. 4, pp. 1839–1841, 2001.
[53]  Z. Jiang, M. M. Yang, M. Sullivan, J. L. Chao, and M. Russak, “Effect of micro-waviness and design of landing zones with a glide avalanche below 0.5 " for conventional pico sliders,” IEEE Transactions on Magnetics, vol. 35, no. 5, pp. 2370–2372, 1999.
[54]  B. Marchon, D. Kuo, S. Lee, J. Gui, and G. C. Rauch, “Glide avalanche prediction from surface topography,” Transactions of the ASME Journal of Tribology, vol. 118, no. 3, pp. 644–650, 1996.
[55]  Q. Dai, U. Nayak, D. Margulies et al., “Tribological issues in perpendicular recording media,” Tribology Letters, vol. 26, no. 1, pp. 1–9, 2007.
[56]  M. F. Toney, C. M. Mate, and K. A. Leach, “Roughness of molecularly thin perfluoropolyether polymer films,” Applied Physics Letters, vol. 77, no. 20, pp. 3296–3298, 2000.
[57]  R. Pit, B. Marchon, S. Meeks, and V. Velidandla, “Formation of lubricant "moguls" at the head/disk interface,” Tribology Letters, vol. 10, no. 3, pp. 133–142, 2001.
[58]  X. Ma, H. Tang, M. Stirniman, and J. Gui, “Lubricant thickness modulation induced by head-disk dynamic interactions,” IEEE Transactions on Magnetics, vol. 38, no. 1, pp. 112–117, 2002.
[59]  Q. Dai, F. Hendriks, and B. Marchon, “Modeling the washboard effect at the head/disk interface,” Journal of Applied Physics, vol. 96, no. 1, pp. 696–703, 2004.
[60]  I. Takekuma, H. Nemoto, H. Matsumoto, et al., “Capped L1(0)-ordered FePt granular media with reduced surface roughness,” Journal of Applied Physics, vol. 111, Article ID 07B708, 3 pages, 2012.
[61]  N. Wang and K. Komvopoulos, “Thermal stability of ultrathin amorphous carbon films for energy-assisted magnetic recording,” IEEE Transactions on Magnetics, vol. 47, pp. 2277–2282, 2011.
[62]  N. Tagawa, H. Tani, and K. Ueda, “Experimental investigation of local temperature increase in disk surfaces of hard disk drives due to laser heating during thermally assisted magnetic recording,” Tribology Letters, vol. 44, pp. 81–87, 2011.
[63]  N. Tagawa, H. Andoh, and H. Tani, “Study on lubricant depletion induced by laser heating in thermally assisted magnetic recording systems: effect of lubricant thickness and bonding ratio,” Tribology Letters, vol. 37, no. 2, pp. 411–418, 2010.
[64]  C. Choi, Y. Yoon, D. Hong, Y. Oh, F. E. Talke, and S. Jin, “Planarization of patterned magnetic recording media to enable head flyability,” Microsystem Technologies, vol. 17, pp. 395–402, 2011.
[65]  H. Li and F. E. Talke, “Numerical simulation of the head/disk interface for bit patterned media,” IEEE Transactions on Magnetics, vol. 45, no. 11, pp. 4984–4989, 2009.

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