Structural and tribological characterization of protective amorphous diamond-like carbon and amorphous CNx overcoats for next generation hard disks

被引:208
作者
Scharf, TW [1 ]
Ott, RD
Yang, D
Barnard, JA
机构
[1] Univ Alabama, Ctr Mat Informat Technol, Tuscaloosa, AL 35487 USA
[2] Univ Alabama, Dept Met & Mat Engn, Tuscaloosa, AL 35487 USA
关键词
D O I
10.1063/1.369654
中图分类号
O59 [应用物理学];
学科分类号
摘要
Further insight into processing-structure-property relationships have been carried out for existing and candidate carbon-based protective overcoats used in the magnetic recording industry. Specifically, 5 nm thick amorphous diamond-like carbon (a:C) and nitrogenated diamond-like carbon (a:CNx) overcoats were deposited by low deposition rate sputtering onto a thin film disk consisting of either CoCrPt/CrV/NiP/AlMg or CoCrPt/CrV/glass. The wear durability and frictional behavior of these hard disks were ascertained using a recently developed depth sensing reciprocating nanoscratch test. It was determined that the CN0.14/CoCrPt/CrV/ glass disk exhibited the most wear resistance, least amount of plastic deformation, and lowest kinetic friction coefficient after the last wear event. Core level x-ray photoelectron spectroscopy (XPS) results of sputter cleaned overcoats indicated that nitrogen up to 14 at. % incorporated into the amorphous network resulted in these improvements near the overcoat/magnetic layer interface, since there was an increase in the number of N-sp(3) C bonded sites in a predominantly N-sp(2) C bonded matrix. However, nonsputter cleaned overcoats exhibited a more graphitic pyridine-like (nondoping configuration) structure near the surface as evidenced by the increase in C=N versus C-N bonds and the valence band XPS determined appearance of the 2p-pi band near the Fermi level (E-F). Therefore, XPS sputter cleaning revealed a gradient in the chemical nature of the overcoats through the thickness. In addition, micro-Raman spectroscopy established that a further increase of nitrogen (greater than or equal to 18 at. %) weakened the overcoat structure due to the formation of terminated sites in the amorphous carbon network, since nitrogen failed to connect the sp(2) domains within the network. This, in conjunction with an increase in the intensity of the 2p-pi band from the valence band XPS spectra and the increase in the G-band position and I-D/I-G ratio from the Raman spectra, confirmed the increase in the size and number of sp(2) bonds in the CN0.18 overcoat. (C) 1999 American Institute of Physics. [S0021-8979(99)02406-8].
引用
收藏
页码:3142 / 3154
页数:13
相关论文
共 46 条
[1]  
ANDERS S, 1997, DATA STORAGE, V4, P31
[2]  
[Anonymous], 1990, TRIBOLOGY MECH MAGNE
[3]  
BARBER M, 1973, J CHEM SOC F2, V69, P551
[4]  
Beamson G., 1993, Adv. Mater., V5, P778, DOI DOI 10.1002/ADMA.19930051035
[5]   MODELING STUDIES OF AMORPHOUS-CARBON [J].
BEEMAN, D ;
SILVERMAN, J ;
LYNDS, R ;
ANDERSON, MR .
PHYSICAL REVIEW B, 1984, 30 (02) :870-875
[6]   Determination of the structure of amorphous nitrogenated carbon films by combined Raman and x-ray photoemission spectroscopy [J].
Bhattacharyya, S ;
Hong, J ;
Turban, G .
JOURNAL OF APPLIED PHYSICS, 1998, 83 (07) :3917-3919
[7]   Spectroscopic determination of the structure of amorphous nitrogenated carbon films [J].
Bhattacharyya, S ;
Cardinaud, C ;
Turban, G .
JOURNAL OF APPLIED PHYSICS, 1998, 83 (08) :4491-4500
[8]  
Bhushan B, 1995, ADV INFO STORAGE SYS, V6, P193
[9]   MULTI-PASS SCRATCH TESTING AS A MODEL FOR ABRASIVE WEAR [J].
BULL, SJ ;
RICKERBY, DS .
THIN SOLID FILMS, 1989, 181 :545-553
[10]   CHEMICAL-STRUCTURE AND PHYSICAL-PROPERTIES OF DIAMOND-LIKE AMORPHOUS-CARBON FILMS PREPARED BY MAGNETRON SPUTTERING [J].
CHO, NH ;
KRISHNAN, KM ;
VEIRS, DK ;
RUBIN, MD ;
HOPPER, CB ;
BHUSHAN, B ;
BOGY, DB .
JOURNAL OF MATERIALS RESEARCH, 1990, 5 (11) :2543-2554