Head structure for thermally-assisted recording (TAR) disk drive
View Patent ↗A thermally-assisted recording (TAR) head structure has a semiconductor substrate as the head carrier with a vertical-cavity surface-emitting laser (VCSEL) on its front surface, a TAR head formed directly on the VCSEL, and a highly reflecting third mirror on its back surface. The semiconductor substrate serves as an extended cavity for the VCSEL. The TAR head is fabricated on the outer surface of the VCSEL in the same manner as proposed for fabrication of a TAR head on a conventional slider. The TAR head includes a conventional read head and write head, and an optical waveguide with a grating coupler and a near-field transducer (NFT). The laser radiation is output through a partially reflecting output mirror of the VCSEL through the front surface to the grating coupler, which turns the incoming laser radiation 90 degrees and directs it into the waveguide from where it is directed to the NFT.
1. A thermally-assisted recording (TAR) head structure for a magnetic recording disk drive comprising:
a semiconductor substrate having a back surface and a front surface generally parallel to said back surface;
a vertical cavity surface emitting laser (VCSEL) on said front surface, the VCSEL having a laser radiation output surface generally parallel to said front surface, the laser radiation being output in a direction substantially perpendicular to said output surface;
a back mirror on said back surface, the semiconductor substrate between the back mirror and the VCSEL forming an extended cavity for the VCSEL;
a TAR head formed on and in contact with the VCSEL output surface, the TAR head comprising:
a layer of electrically insulating material, the insulating layer having a disk-facing surface generally orthogonal to said back and front semiconductor substrate surfaces;
an optical waveguide oriented generally parallel to said output surface, the waveguide having a grating coupler for directing laser radiation from the output surface to the waveguide;
a near-field transducer (NFT) coupled to the waveguide and located at the disk-facing surface for receipt of laser radiation from the waveguide;
a write head having a write pole at the disk-facing surface; and
a magnetoresistive read head having a sensing edge at the disk-facing surface.
2. The head structure of claim 1 wherein the semiconductor substrate has a disk-facing surface substantially coplanar with the disk-facing surface of said insulating layer.
3. The head structure of claim 1 wherein the semiconductor substrate comprises a material selected from GaAs and AlGaAs.
4. The head structure of claim 1 wherein the VCSEL comprises a partially-reflecting output mirror, a partially-reflecting intermediate mirror between said back mirror and the output mirror, and an oxide layer having an aperture therein and located between the intermediate mirror and the output mirror.
5. The head structure of claim 4 further comprising a first electrode for providing electrical connection to the substrate and a second electrode for providing electrical connection to the output mirror.
6. The head structure of claim 1 wherein the TAR head further comprises two shield layers of magnetically permeable material and wherein the read head is located between the two shield layers.
7. The head structure of claim 1 wherein the write head further comprises a return pole magnetically coupled to the write pole.
8. The head structure of claim 1 wherein the write head further comprises an electrically conductive coil for generating magnetic flux in the write pole when electrical current is passed through the coil.
9. The head structure of claim 1 wherein the coil is a helical coil wrapped around the write pole.
10. The head structure of claim 1 wherein the coil is a flat coil.
11. The head structure of claim 1 wherein the substantially coplanar disk-facing surfaces of the semiconductor substrate and insulating layer are an air-bearing surface.
12. A thermally-assisted perpendicular magnetic recording disk drive comprising:
a perpendicular magnetic recording disk comprising a disk substrate and a perpendicular magnetic recording layer on the disk substrate; and
the head structure of claim 1 ; wherein the head structure is maintained near the disk with the spacing between the NFT and the recording layer being less than the wavelength of the laser radiation.
13. The disk drive of claim 12 wherein the perpendicular magnetic recording layer is patterned into discrete data islands.