Abstract:
Embodiments herein generally relate to TMR readers and methods for their manufacture. The embodiments discussed herein disclose TMR readers that utilize a structure that avoids use of the DLC layer over the sensor structure and over the hard bias layer. The capping structure over the sensor structure functions as both a protective layer for the sensor structure and a CMP stop layer. The hard bias capping structure functions as both a protective structure for the hard bias layer and as a CMP stop layer. The capping structures that are free of DLC reduce the formation of notches in the second shield layer so that second shield layer is substantially flat.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    Embodiments of the present invention generally relate to a tunnelling magnetoresistive (TMR) reader and a method for its manufacture. 
         [0003]    2. Description of the Related Art 
         [0004]    TMR readers are used in hard disk drives to read bits of data from the hard disk drive. An example of a TMR reader is shown in  FIGS. 1A and 1B . The TMR reader  100  includes a first shield layer  102  and a sensor structure including a pinned layer  104 , a barrier layer  106 , a free layer  108  and a cap layer  110 . The sensor structure may be fabricated by depositing all of the layers of the sensor structure and then depositing a diamond-like carbon (DLC) layer  112  thereover. A photoresist mask is then formed over the DLC layer. The DLC layer  112 , as well as the layers of the sensor structure, are then patterned to form the sensor structure shown in  FIG. 1A . During the etching, material from the various layers of the sensor structure may redeposit on the photoresist mask. 
         [0005]    While the photoresist mask and DLC layer  112  are still present, an insulating layer  114  is deposited on top of the exposed first shield layer  102  and the sidewalls of the sensor structure. A hard bias layer  116  and a hard bias capping layer  118  are formed over the insulating layer  114 . A second DLC layer  120  is formed over the exposed insulating layer  114 , hard bias layer  116  and hard bias capping layer  118 . The second DLC layer  120  and the first DLC layer  112  are used as chemical mechanical polishing (CMP) stop layers to protect the hard bias layer  116  and sensor structure during a CMP lift-off process that occurs later. The first and second DLC layers  112 ,  120  may have different thicknesses. 
         [0006]    The DLC layers  112 ,  120  have several drawbacks. First, the first and second DLC layers  112 ,  120  are deposited in a tool that is separate from the tool used to deposit the hard bias capping layer  118  and the cap layer  110 . Thus, depositing the DLC layers  112 ,  120  add process complication and increase the cost of manufacturing the TMR reader. Second, the DLC layers  112 ,  120  are typically removed using a reactive ion etching (RIE) process which adds process complication and cost. Third, the DLC layers  112 ,  120  may delaminate during the CMP process and thus could result in overpolishing of the TMR reader which leads to poor device performance. Finally, the different thicknesses of the DLC layers  112 ,  120  may make it difficult to achieve a truly planarized second shield layer  112  (See  FIG. 1B ) and thus result in a notch  124  in the second shield layer  122 . 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention generally relates to a TMR reader and a method for its manufacture. During the manufacture of a TMR reader, a DLC layer may be used as a CMP stop layer. The DLC layer is typically disposed over capping layers that are used to protect the hard bias layer and the sensor structure. The DLC layer can cause complications such as increased processing time and cost. The embodiments discussed herein disclose TMR readers that utilize a much simpler structure that replaces not only the DLC layer, but also the capping layer, which saves processing time and cost. 
         [0008]    In one embodiment, a method includes forming a sensor structure over a first shield layer. The sensor structure has a top surface and sidewalls. The method also includes depositing a first insulating layer over the first shield layer and the sidewalls of the sensor structure, depositing a hard bias layer over the first insulating layer, and forming a hard bias capping structure over the hard bias layer. The hard bias capping structure is free of DLC. In one embodiment, the hard bias capping structure is selected from the group consisting of: a first multiple layer structure comprising a tantalum layer formed on the hard bias layer and an iridium layer formed on the tantalum layer, a second multiple layer structure comprising an iridium layer formed on the hard bias layer and a layer of either tantalum or chromium or ruthenium formed on the iridium layer, a third multiple layer structure comprising a rhodium layer formed on the hard bias layer and a layer of either tantalum or chromium or ruthenium formed on the rhodium layer, and an iridium layer formed on the hard bias layer. The method also includes depositing a second shield layer over the sensor structure and the hard bias capping structure. 
         [0009]    In another embodiment, a method includes forming a sensor structure over a first shield layer. The sensor structure has a top surface and sidewalls. The sensor structure additionally has a pinned layer disposed on the first shield layer, a barrier layer disposed on the pinned layer, a free layer disposed on the barrier layer, and a capping layer structure disposed on the barrier layer. The capping layer structure is free of DLC. In one embodiment, the capping layer structure is selected from the group consisting of an iridium layer deposited on the barrier layer, a rhodium layer deposited on the barrier layer, an iridium layer deposited on the barrier layer and a rhodium layer deposited on the iridium layer, and a rhodium layer deposited on the barrier layer and an iridium layer deposited on the rhodium layer. The method also includes depositing a first insulating layer over the first shield layer and the sidewalls of the sensor structure, depositing a hard bias layer over the first insulating layer, forming a hard bias capping structure over the hard bias layer, and depositing a second shield layer over the sensor structure and the hard bias capping structure. 
         [0010]    In another embodiment, a TMR reader includes a first shield layer having a first portion and a second portion, a sensor structure disposed over the first portion of the first shield layer and having a top surface and sidewalls, an insulating layer disposed over the second portion of the first shield layer and the sidewalls, a hard bias layer disposed over the insulating layer, and a hard bias capping structure disposed over the hard bias layer. The hard bias capping structure is free of DLC. In one embodiment, the hard bias capping structure is selected from the group consisting of a first multiple layer structure comprising a tantalum layer formed on the hard bias layer and an iridium layer formed on the tantalum layer, a second multiple layer structure comprising an iridium layer formed on the hard bias layer and a layer of either tantalum or chromium or ruthenium formed on the iridium layer, a third multiple layer structure comprising a rhodium layer formed on the hard bias layer and a layer of either tantalum or chromium or ruthenium formed on the rhodium layer, and an iridium layer formed on the hard bias layer. The TMR reader also includes a second shield layer over the sensor structure and the hard bias capping structure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. 
           [0012]      FIGS. 1A and 1B  are schematic cross-sectional views of a prior art TMR magnetic read sensor. 
           [0013]      FIGS. 2A and 2B  are schematic cross-sectional views of a TMR magnetic read sensor according to one embodiment. 
           [0014]      FIGS. 3A and 3B  are schematic cross-sectional views of a TMR magnetic read sensor according to another embodiment. 
           [0015]      FIGS. 4A and 4B  are schematic cross-sectional views of a TMR magnetic read sensor according to another embodiment. 
       
    
    
       [0016]    To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. 
       DETAILED DESCRIPTION 
       [0017]    In the following, reference is made to embodiments of the invention. However, it should be understood that the invention is not limited to specific described embodiments. Instead, any combination of the following features and elements, whether related to different embodiments or not, is contemplated to implement and practice the invention. Furthermore, although embodiments of the invention may achieve advantages over other possible solutions and/or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the invention. Thus, the following aspects, features, embodiments and advantages are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). Likewise, reference to “the invention” shall not be construed as a generalization of any inventive subject matter disclosed herein and shall not be considered to be an element or limitation of the appended claims except where explicitly recited in a claim(s). 
         [0018]    Embodiments disclosed herein generally relate to TMR readers and methods for their manufacture. During the manufacture of a TMR reader, a DLC layer may be used as a CMP stop layer. The DLC layer is typically disposed over capping layers that are used to protect the hard bias layer and the sensor structure. The DLC layer can cause complications such as increased processing time and cost. The embodiments discussed herein disclose TMR readers that utilize a much simpler structure that replaces not only the DLC layer, but also the capping layer, which saves processing time and cost. 
         [0019]    Hard Bias Capping Structure 
         [0020]      FIGS. 2A and 2B  are schematic cross-sectional views of a TMR magnetic read sensor  200  according to one embodiment. The magnetic read sensor  200  includes a first shield layer  202 . The first shield layer  202  may comprise a ferromagnetic material. Suitable ferromagnetic materials that may be utilized include Ni, Fe, Co, NiFe, NiFeCo, NiCo, CoFe and combinations thereof. 
         [0021]    The magnetic read sensor  200  also includes a sensor structure comprising a pinned magnetic layer  204 , a barrier layer  206 , a free magnetic layer  208  and a capping layer  210 . The pinned magnetic layer  204  may be one of several types of pinned layers, such as a simple pinned, antiparallel pinned, self pinned or antiferromagnetic pinned sensor. For purposes of simplicity, the sensor will be described herein as an antiparallel pinned, antiferromagnetic pinned sensor having a first antiparallel layer, a second antiparallel layer, and a non-magnetic, antiferromagnetic coupling layer, such as Ru sandwiched therebetween. The first and second antiparallel layers can be constructed of several magnetic materials such as, for example NiFe or CoFe, and have magnetic moments that are pinned by exchange coupling of the first antiparallel layer with a layer of antiferromagnetic layer. The antiferromagnetic layer may include materials such as PtMn, iridium, or rhodium. The barrier layer  206  may comprise an insulating material such as alumina or magnesium oxide. The free magnetic layer  208  may comprise ferromagnetic material such as Co, CoFe, NiFe or combinations thereof. The cap layer  210  may comprise a material to protect the sensor from damage such as ruthenium or tantalum. 
         [0022]    The layers of the sensor structure may be blanket deposited and then etched back. To etch back the layers, a diamond like carbon (DLC) layer  224  and a photoresist mask  218  may be formed thereover. The DLC layer  224  is used to protect the sensor structure during a CMP process. The layers of the sensor structure may then be etched in the areas not covered by the photoresist mask  218 . During the etching, material removed from the sensor structure may deposit on the photoresist mask as a hard, crust layer  220 . 
         [0023]    Following the formation of the sensor structure, an insulating layer  212  may be deposited on the first shield layer  202  as well as the sidewalls of the sensor structure. The insulating layer  212  may comprise an insulating material such as aluminum oxide. The insulating layer  212  may be deposited by well known deposition methods such as atomic layer deposition (ALD), chemical vapor deposition (CVD), sputtering, etc. After the insulating layer  212  is deposited, a hard bias layer  214  is then deposited. The hard bias layer  214  may comprise a material having a high magnetic moment such as CoFe. 
         [0024]    Once the hard bias layer  214  is deposited, the new hard bias capping structure  216  may be formed. In a first embodiment, the new hard bias capping structure  216  may comprise a multiple layer structure comprising a first tantalum layer, an iridium layer, and a second tantalum layer. The first tantalum layer may be deposited to a thickness of up to about 20 Angstroms and functions as a glue layer for the iridium layer. The iridium layer may be deposited to a thickness of between about 20 Angstroms and about 150 Angstroms. The second tantalum layer may be deposited to a thickness of between about 20 Angstroms and about 150 Angstroms. The second tantalum layer provides a planarization after a CMP step that will be described later for removing the photoresist mask  218 . The second tantalum layer also is used for glancing milling consumption for a touch CMP lift-off based process that is used to remove the photoresist mask  218  in a later step. Other materials that may be used for the second tantalum layer instead of tantalum include chromium or ruthenium. 
         [0025]    In a second embodiment, the new hard bias capping structure  216  may comprise a first glue layer of tantalum having a thickness of up to about 20 Angstroms. The first glue layer is deposited on the hard bias layer  214 . Over the first glue layer, a layer of iridium is deposited to a thickness of between about 20 Angstroms and about 150 Angstroms. The iridium or rhodium layer is used as a CMP stop layer when removing the photoresist mask  218 . 
         [0026]    In a third embodiment, the new hard bias capping structure  216  may comprise a two layer structure in which the first layer comprises iridium or rhodium and is deposited on the hard bias layer  214 . The first layer may have a thickness of between about 20 Angstroms and about 150 Angstroms. The second layer is deposited on the first layer and may comprise tantalum, chromium or ruthenium. The second layer may be deposited to a thickness of between about 20 Angstroms and about 150 Angstroms. 
         [0027]    In a fourth embodiment, the new hard bias capping structure  216  may comprise a single layer of iridium having a thickness of between about 20 Angstroms and about 150 Angstroms. 
         [0028]    The fabrication process may proceed according to several embodiments. In a first process embodiment, the sensor structure is formed over the first shield layer  202 . The insulating layer  212  and hard bias layer  216  are then formed. The hard bias capping structure  216  of either the first embodiment, the second embodiment, or the third embodiment is then deposited. The second and fourth embodiments are not utilized in the first process embodiment because the second and fourth embodiments have iridium as the topmost layer in the hard bias capping structure  216 . The hard bias capping structure  216  may be deposited by a sputtering method. Due to the hard, crust layer  220 , a glancing mill process may be performed to open the photoresist mask  218 . The photoresist mask  218  may then be removed by rinsing the photoresist mask  218  in a solution and performing a CMP process. The DLC layer  224  may be removed by an RIE process. A touch CMP process is then performed to remove fencing and provide some planarization of the hard bias capping structure  216  as well as the cap layer  210 . A second shield layer  222  is then deposited. The second shield layer  222  may comprise a ferromagnetic material. Suitable ferromagnetic materials that may be utilized include Ni, Fe, Co, NiFe, NiFeCo, NiCo, CoFe and combinations thereof. 
         [0029]    In a second process embodiment, the sensor structure is formed over the first shield layer  202 . The insulating layer  212  and hard bias layer  216  are then formed. The hard bias capping structure  216  of any of the first through fourth embodiment is then deposited. A wrinkle baking process is performed to expand the photoresist mask  218  and crack the hard, crust layer  220 . The photoresist mask  218  is then removed by dipping the photoresist mask  218  in a solution and performing a CMP process. The DLC layer  224  may be removed by an RIE process. A CMP process is then performed to remove any fencing and to provide some planarization of the hard bias capping structure  216  as well as the cap layer  210 . A second shield layer  222  is then deposited. 
         [0030]    Thus, in the embodiment shown in  FIGS. 2A-2B , no DLC layer is utilized over the hard bias layer  214  or the hard bias capping structure  216 . The four embodiments discussed above replace the hard bias capping layer  118  and DLC layer  120  shown in  FIG. 1A . 
         [0031]    Sensor Structure Capping Structure 
         [0032]      FIGS. 3A and 3B  are schematic cross-sectional views of a TMR magnetic read sensor  300  according to another embodiment. The magnetic read sensor  300  includes a first shield layer  302 . The first shield layer  302  may comprise the same materials as discussed above in regards to the first shield layer  202  of sensor  200 . 
         [0033]    The magnetic read sensor  300  also includes a sensor structure comprising a pinned magnetic layer  304 , a barrier layer  306 , a free magnetic layer  308  and a capping structure  310 . The pinned magnetic layer  304 , barrier layer  306  and free magnetic layer  308  may comprise materials as discussed above in regards to layers  204 ,  206 ,  208 . The capping structure  310  may be deposited over the free magnetic layer  308 . In a first embodiment, the capping structure  310  may comprise an iridium layer deposited on the free magnetic layer  308 . In a second embodiment, the capping structure  310  may comprise a rhodium layer deposited on the free magnetic layer  308 . In a third embodiment, the capping structure  310  may comprise a bottom layer of iridium deposited on the free magnetic layer  308  and a top layer of rhodium deposited on the bottom layer of iridium. In a fourth embodiment, the capping structure  310  may comprise a bottom layer of rhodium deposited on the free magnetic layer  308  and a top layer of iridium deposited on the bottom layer of rhodium. The capping structure  310  may have a thickness of between about 20 Angstroms and about 150 Angstroms. The capping structure  310  does not include a DLC layer. The capping structure  310  operates as a CMP stop layer to protect the sensor structure during the lift-off of the photoresist mask  312 . 
         [0034]    Once the layers of the sensor structure have been deposited and etched, an insulating layer  314 , a hard bias layer  316  and a hard bias capping layer  318  may be deposited. A DLC layer  320  may be deposited over the hard bias capping layer  318 . Once the DLC layer  320  and the photoresist mask  312  are removed, a second shield layer  322  is deposited. The materials for the second shield layer  322  may comprise the same materials as discussed above for second shield layer  222 . 
         [0035]    The fabrication process may proceed according to any of several embodiments. In a first process embodiment, the sensor structure is formed over the first shield layer  302 . The photoresist mask  312  is then formed without first depositing a DLC layer over the capping structure  310 . The sensor structure is then etched. The insulating layer  314  and hard bias layer  316  are then formed. The hard bias capping layer  318  is then deposited. Due to the hard, crust layer that may form on the photoresist mask  312 , a glancing mill process may be performed to open the photoresist mask  312 . The photoresist mask  312  may then be removed by rinsing the photoresist mask  312  in a solution and performing a CMP process. The DLC layer  320  may be removed by an RIE process. A CMP process is then performed provide some planarization of the hard bias capping layer  318  as well as the capping structure  310 . The second shield layer  322  is then deposited. 
         [0036]    In a second process embodiment, the sensor structure is formed over the first shield layer  302 . The photoresist mask  312  is then formed without first depositing a DLC layer over the capping structure  310 . The sensor structure is then etched. The insulating layer  314  and hard bias layer  316  are then formed. The hard bias capping layer  318  is then deposited. A wrinkle baking process is performed to expand the photoresist mask  312  and crack the hard, crust layer. The photoresist mask  312  is then removed by dipping the photoresist mask  312  in a solution and performing a CMP process. The DLC layer  320  may be removed by an RIE process. A CMP process is then performed to provide some planarization of the hard bias capping structure  318  as well as the capping structure  310 . The second shield layer  222  is then deposited. 
         [0037]    Thus, in the embodiment shown in  FIGS. 3A-3B , no DLC layer is utilized over the sensor structure. The capping structure  310  replace the capping layer  110  and DLC layer  112  shown in  FIG. 1A . 
         [0038]    Hard Bias and Sensor Structure Capping 
         [0039]    In another embodiment, the elimination of both DLC layers  112 ,  120  is contemplated.  FIGS. 4A and 4B  are schematic cross-sectional views of a TMR magnetic read sensor  400  according to another embodiment in which no DLC layer is utilized. The magnetic read sensor  400  includes a first shield layer  402 . The first shield layer  402  may comprise the same materials as discussed above in regards to the first shield layer  202  of sensor  200 . 
         [0040]    The magnetic read sensor  400  also includes a sensor structure comprising a pinned magnetic layer  404 , a barrier layer  406 , a free magnetic layer  408  and a capping structure  410 . The pinned magnetic layer  404 , barrier layer  406  and free magnetic layer  408  may comprise materials as discussed above in regards to layers  404 ,  406 ,  408 . The capping structure  410  may be deposited over the free magnetic layer  408 . In a first embodiment, the capping structure  410  may comprise an iridium layer deposited on the free magnetic layer  408 . In a second embodiment, the capping structure  410  may comprise a rhodium layer deposited on the free magnetic layer  408 . In a third embodiment, the capping structure  410  may comprise a bottom layer of iridium deposited on the free magnetic layer  408  and a top layer of rhodium deposited on the bottom layer of iridium. In a fourth embodiment, the capping structure  410  may comprise a bottom layer of rhodium deposited on the free magnetic layer  408  and a top layer of iridium deposited on the bottom layer of rhodium. The capping structure  410  may have a thickness of between about 20 Angstroms and about 150 Angstroms. The capping structure  410  does not include a DLC layer. The capping structure  410  operates as a CMP stop layer to protect the sensor structure during the lift-off of the photoresist mask  412 . 
         [0041]    Once the layers of the sensor structure have been deposited and etched, an insulating layer  414 , a hard bias layer  416  and a hard bias capping structure  418  may be deposited. A DLC layer is not utilized over the hard bias capping structure  418 . 
         [0042]    In a first embodiment, the hard bias capping structure  418  may comprise a multiple layer structure comprising a first tantalum layer, an iridium layer, and a second tantalum layer. The first tantalum layer may be deposited to a thickness of up to about 20 Angstroms and functions as a glue layer for the iridium layer. The iridium layer may be deposited to a thickness of between about 20 Angstroms and about 150 Angstroms. The second tantalum layer may be deposited to a thickness of between about 20 Angstroms and about 150 Angstroms. The second tantalum layer provides a planarization after a chemical mechanical polishing (CMP) step that will be described later for removing the photoresist mask  412 . The second tantalum layer also is used for glancing milling consumption for a touch CMP lift-off based process that is used to remove the photoresist mask  412  in a later step. Other materials that may be used for the second tantalum layer instead of tantalum include chromium or ruthenium. 
         [0043]    In a second embodiment, the hard bias capping structure  418  may comprise a first glue layer of tantalum having a thickness of up to about 20 Angstroms. The first glue layer is deposited on the hard bias layer  416 . Over the first glue layer, a layer of iridium is deposited to a thickness of between about 20 Angstroms and about 150 Angstroms. The iridium layer is used as a CMP stop layer when removing the photoresist mask  412 . 
         [0044]    In a third embodiment, the hard bias capping structure  418  may comprise a two layer structure in which the first layer comprises iridium or rhodium and is deposited on the hard bias layer  416 . The first layer may have a thickness of between about 20 Angstroms and about 150 Angstroms. The second layer is deposited on the first layer and may comprise tantalum, chromium or ruthenium. The second layer may be deposited to a thickness of between about 20 Angstroms and about 150 Angstroms. 
         [0045]    In a fourth embodiment, the hard bias capping structure  418  may comprise a single layer of iridium having a thickness of between about 20 Angstroms and about 150 Angstroms. 
         [0046]    The fabrication process may proceed according to several embodiments. In a first process embodiment, the sensor structure is formed over the first shield layer  402 . The photoresist mask  412  is then formed without first depositing a DLC layer over the capping structure  410 . The sensor structure is then etched. The insulating layer  414  and hard bias layer  416  are then formed. The hard bias capping structure  418  of either the first embodiment or the third embodiment is then deposited without utilizing a DLC layer. The second and fourth embodiments are not utilized in the first process embodiment because the second and fourth embodiments have iridium as the topmost layer in the hard bias capping structure  418 . The hard bias capping structure  418  may be deposited by a sputtering method. A glancing mill process may be performed to open the photoresist mask  412 . The photoresist mask  412  may then be removed by rinsing the photoresist mask  412  in a solution and performing a CMP process. A touch CMP process is then performed to remove fencing and provide some planarization of the hard bias capping structure  418  as well as the cap structure  410 . The second shield layer  420  is then deposited. 
         [0047]    In a second process embodiment, the sensor structure is formed over the first shield layer  402 . The photoresist mask  412  is then formed without first depositing a DLC layer over the capping structure  410 . The sensor structure is then etched. The insulating layer  414  and hard bias layer  416  are then formed. The hard bias capping structure  418  of any of the first through fourth embodiment is then deposited without utilizing a DLC layer. A wrinkle baking process is performed to expand the photoresist mask  412  and crack the hard, crust layer. The photoresist mask  412  is then removed by dipping the photoresist mask  412  in a solution and performing a CMP process. A CMP process is then performed to remove any fencing and to provide some planarization of the hard bias capping structure  418  as well as the capping structure  410 . The second shield layer  222  is then deposited. 
         [0048]    Thus, in the embodiment shown in  FIGS. 4A-4B , no DLC layers are utilized in the fabrication of the magnetic read sensor  400 . The capping structure  410  replaces the capping layer  110  and DLC layer  112  shown in  FIG. 1A . The hard bias capping structure  418  replaces both the hard bias capping layer  118  and the DLC layer  118  shown in  FIG. 1A . A silicon adhesion layer may be utilized between the hard bias capping structure  418  and the hard bias layer  416  if desired. Similarly, a silicon adhesion layer may be utilized between the capping structure  410  and the free magnetic layer  408  if desired. 
         [0049]    The same capping material may be used for both the capping structure  410  and the hard bias capping structure  418 . Additionally, the iridium or rhodium may be used for the antiferromagnetic coupling layer in the pinned magnetic layer of the sensor structure. Thus, iridium or rhodium may be used for both the sensor itself and for the capping. The iridium or rhodium may be deposited from a sputtering target. By eliminating one or both DLC layers in a TMR magnetic read sensor, fabrication costs may be reduced. 
         [0050]    While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.