1. A photoacoustic compression method for machining a transparent target material, comprising the steps of:
applying a laser beam having at least one burst of laser pulses, said laser beam operating at a wavelength less than 5 \u03bcm, a laser burst pulse repetition rate between 1 Hz to 2 MHz having a number of subpulses in the range of 1 to 50 per burst of said laser pulses, and, each pulse having burst pulse energy of 5-500 \u03bcJ, from a laser beam source to a distributive focus lens focusing assembly which focuses said laser pulses, prior to application of said laser pulses to said surface of said transparent target;
total pulse energy or fluence applied to said transparent target at a spot where said laser pulses contact a surface of said transparent target, said spot being the point of initiation of machining on said transparent target determined by said wavelength, said laser burst pulse repetition rate, said number of subpulses per burst, and said burst pulse energy; and,
adjusting said wavelength, adjusting said laser burst pulse repetition rate, adjusting said number of subpulses per burst, and adjusting said energy per pulse to initiate and propagate photoacoustic compression machining, and prevent ablative machining.
2. The photoacoustic compression method for machining a transparent target material, as claimed in claim 1, wherein said focusing comprises:
delivering said laser pulses to said surface of said transparent target after adjustment of the relative distance or angle of said distributive focus lens focusing assembly in relation to said laser source;
focusing said laser pulses in said distributive focus lens focusing assembly so as to create a principal focal waist and at least one secondary focal waist; and,
adjusting said principal focal waist such that said principal focal waist does not reside on or in said transparent target that is being machined.
3. The photoacoustic compression method for machining a transparent target material, as claimed in claim 1, wherein said focusing comprises:
delivering said laser pulses to said surface of said transparent target after adjustment of the relative distance or angle of said distributive focus lens focusing assembly in relation to said laser source; and,
focusing said laser pulses in said distributive focus lens focusing assembly so as to create a principal focal waist and at least one secondary focal waist; and,
adjusting said transparent target distance with respect to said principal focal waist and at least one secondary focal waist.
4. The photoacoustic compression method for machining a transparent target material, as claimed in claim 2, further comprising the steps of:
adjusting said focus of said laser pulses such that said spot is located below or above said principal focal waist, said spot has a diameter larger than a diameter of a filament formed in said transparent target.
5. The photoacoustic compression method for machining a transparent target material, as claimed in claim 3, further comprising the steps of:
adjusting said focus of said laser pulses such that said spot is located below or above said principal focal waist, said spot has a diameter larger than a diameter of a filament formed in said transparent target.
6. The photoacoustic compression method for machining a transparent target material, as claimed in claim 2, wherein said transparent target may be comprised of one or a set of transparent wafers, plates or substrates in a layered configuration; and wherein machining of said transparent target is the drilling of stopped or through orifices beginning at any depth and in any one of said set of wafers, plates or substrates in said layered configuration.
7. The photoacoustic compression method for machining a transparent target material, as claimed in claim 3, wherein said transparent target may be comprised of one or a set of transparent wafers, plates or substrates in a layered configuration; and wherein machining of said transparent target is the drilling of stopped or through orifices beginning at any depth and in any one of said set of wafers, plates or substrates in said layered configuration.
8. The photoacoustic compression method for machining a transparent target material, as claimed in claim 1, wherein said transparent target may be comprised of one or a set of transparent wafers, plates or substrates in a layered configuration; and wherein machining of said transparent target is the drilling of stopped or through orifices beginning at any depth and in any one of said set of wafers, plates or substrates in said layered configuration.
9. The photoacoustic compression method for machining a transparent target material, as claimed in claim 2, wherein said distributive focus lens focusing assembly determines said fluence level of said secondary focal waists, said secondary focal waists are of sufficient intensity and number to ensure propagation of said photoacoustic compressive machining through a desired volume of said transparent target.
10. The photoacoustic compression method for machining a transparent target material, as claimed in claim 3, wherein said distributive focus lens focusing assembly determines said fluence level of said secondary focal waists, said secondary focal waists are of sufficient intensity and number to ensure propagation of said photoacoustic compressive machining through a desired volume of said transparent target.
11. The photoacoustic compression method for machining a transparent target material, as claimed in claim 1, wherein said laser pulses have a burst frequency in the range of 100 kHz to 90 MHz to maintain photoacoustic compression within said transparent target, said laser pulses having a pulse width of less than 10 nanoseconds.
12. The photoacoustic compression method for machining a transparent target material, as claimed in claim 1, including applying a sacrificial layer to a surface of said material prior to the said application of said burst of laser pulses.
13. The photoacoustic compression method for machining a transparent target material, as claimed in claim 1, wherein no material from said transparent target material is removed from said transparent target by said photoacoustic compression.
14. The photoacoustic compression method for machining a transparent target material, as claimed in claim 1, wherein said distributive focus lens focusing assembly is selected from the group consisting of: aspheric plates, telecentric lenses, non-telecentric lenses, aspheric lenses, axicon, annularly faceted lenses, custom ground aberrated non-perfect lenses, a combination of positive and negative lenses or a series of corrective plates, and, an optical element tilted with respect to the incident beam.
15. A photoacoustic compression method for machining a transparent target material, comprising the steps of:
applying a laser having at least one burst of laser pulses, said laser operating at a wavelength less than 5 \u03bcm, a laser burst pulse repetition rate between 1 Hz to 2 MHz having a number of subpulses in the range of 1 to 50 per burst of said laser pulses, said laser subpulses have a burst frequency in the range of 100 kHz to 90 MHz, said laser pulses having a pulse width of less than 10 nanoseconds, and, having burst pulse energy of 5-500 \u03bcJ, from a laser source through a distributive lens focusing assembly and to said transparent target;
delivering said laser pulses to said transparent target after adjustment of the relative distance or angle of said distributive focus lens focusing assembly in relation to said laser source so as to focus said laser pulses in a distributed focus configuration creating a principal focal waist and at least one secondary focal waist;
photoacoustic compression machining is produced by said laser pulse energy delivered to said transparent target which initiates a Kerr Effect self focusing which is propagated in said transparent target by additional energy input to said transparent target by said secondary focal waists thus producing a filament within said transparent target; and,
total energy input to said transparent target is below the level required to initiate ablative or vaporization based machining of said transparent target.
16. The photoacoustic compression method for machining a transparent target material, as claimed in claim 15, wherein no material from said transparent target material is removed from said transparent target by said photoacoustic compression.
17. The photoacoustic compression method for machining a transparent target material, as claimed in claim 15, wherein said distributive focus lens focusing assembly is selected from the group consisting of: aspheric plates, telecentric lenses, non-telecentric lenses, aspheric lenses, axicon, annularly faceted lenses, custom ground aberrated non-perfect lenses, a combination of positive and negative lenses or a series of corrective plates, and, an optical element tilted with respect to the incident beam.
18. A photoacoustic compression method for machining a transparent target material, comprising the steps of:
applying a laser having at least one burst of laser pulses, said burst of laser pulse having a number of subpulses in the range of 1 to 50 per burst of said laser pulses, from a laser source through a distributive lens focusing assembly and to said transparent target;
adjusting said distributive focusing assembly position in relation to said laser source and said transparent target;
creating a principal focal waist and at least one secondary focal waist;
photoacoustic compression machining is produced by said laser pulse energy delivered to said transparent target which initiates a Kerr Effect self focusing which is propagated in said transparent target by additional energy input to said transparent target by said secondary focal waists thus producing a filament within said transparent target.
19. The photoacoustic compression method for machining a transparent target material, as claimed in claim 18, wherein no material from said transparent target material is removed from said transparent target by said photoacoustic compression.
20. The photoacoustic compression method for machining a transparent target material, as claimed in claim 18, wherein said distributive focus lens focusing assembly is selected from the group consisting of: aspheric plates, telecentric lenses, non-telecentric lenses, aspheric lenses, axicon, annularly faceted lenses, custom ground aberrated non-perfect lenses, a combination of positive and negative lenses or a series of corrective plates, and, an optical element tilted with respect to the incident beam.
21. The photoacoustic compression method for machining a transparent target material, as claimed in claim 18, further comprising the steps of:
creating a plurality of secondary focal waists within said transparent target.
22. The photoacoustic compression method for machining a transparent target material, as claimed in claim 2, further comprising the steps of:
creating a plurality of secondary focal waists within said transparent target.
23. The photoacoustic compression method for machining a transparent target material, as claimed in claim 1, further comprising the steps of:
creating a principal focal waist above or below said transparent target; and,
creating a plurality of secondary focal waists within said transparent target.
24. The photoacoustic compression method for machining a transparent target material, as claimed in claim 1, wherein said transparent target material is selected from the group consisting of glass, oxide glasses, borosilicate glass, chemically or heat strengthened glass, glass ceramics, Sapphire, glass layered on Sapphire, glass coated with metals, glass coated with polymers, SiC, GaN, and Si wafers.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for manufacturing a vertical Schottky diode with a guard ring on a lightly-doped N-type silicon carbide layer, comprising the steps of:
forming a P-type epitaxial layer on the N-type layer;
implanting N-type dopants in areas of the P-type epitaxial layer to neutralize P-type dopants in these areas, across an entire thickness of the epitaxial layer, to form N-type regions of dopant concentration lower than that of the epitaxial layer, the N-type regions delimiting a P-type guard ring;
forming on an external periphery of the epitaxial layer an insulating layer partially covering the guard ring; and
forming a Schottky contact with at least one of the N-type regions internal to the guard ring.
2. The method of claim 1, wherein additional P-type regions located inside of the guard ring are delimited upon implantation of N-type dopants.
3. The component of claim 1, wherein at least one additional ring located outside of the guard ring is delimited upon implantation of N dopants.
4. The method of claim 1, further comprising the step of etching, prior to the implantation of N dopants, areas of the P-type epitaxial layer down to a depth smaller than the thickness of said epitaxial layer to form P-type protruding portions.
5. The method of claim 4, wherein the guard ring is delimited to comprise a protruding portion located on its outer periphery.
6. The method of claim 5, wherein the insulating layer covers the protruding portion of the guard ring.
7. The method of claim 4, wherein N-type dopants are implanted in a protruding portion of the P-type epitaxial layer down to a depth smaller than the thickness of said portion to form N-type regions located on P-type regions.
8. A method of manufacturing a diode on an N-type silicon carbide layer, comprising acts of:
(A) forming a P-type epitaxial layer on the N-type layer;
(B) implanting N-type dopants in the epitaxial layer to form a plurality of N-type regions delimiting a P-type guard ring; and
(C) forming a Schottky contact that contacts at least one of the N-type regions within an area delimited by the guard ring.
9. The method of claim 8, wherein acts (A)-(C) are performed such that the diode is a Schottky diode.
10. The method of claim 8, wherein acts (A)-(C) are performed such that the diode is a Schottkybipolar diode.
11. The method of claim 8, further comprising an act of:
(D) forming on a periphery of a surface of the epitaxial layer an insulating layer that partially covers the guard ring, such that the Schottky contact only contacts a portion of the guard ring not partially covered by the insulating layer.
12. The method of claim 8, wherein the act (A) comprises forming the epitaxial layer such that the epitaxial layer is more heavily-doped than the N-type layer.
13. The method of claim 8, wherein the act (B) comprises forming the N-type regions such that the N-type regions are less heavily-doped than the guard ring.
14. The method of claim 8, wherein the act (B) comprises forming the N-type regions such that at least two of the N-type regions delimit additional P-type regions within the area delimited by the guard ring.
15. The method of claim 8, wherein the act (B) comprises forming the N-type regions such that at least two of the N-type regions delimit at least one additional P-type ring external to the area delimited by the guard ring.
16. The method of claim 8, further comprising an act of:
(D) prior to performing act (B), etching at least one area of the epitaxial layer to reduce a distance that the at least one area extends perpendicularly from a surface of the N-type layer, such that at least one portion of the epitaxial layer extends further, perpendicularly, from the surface of the N-type layer than the at least one area.
17. The method of claim 8, where the act (B) comprises forming the N-type regions such that the guard ring comprises the at least one portion.
18. The method of claim 8, further comprising an act of:
(D) prior to performing act (B), forming a mask on the epitaxial region defining lateral dimensions of the N-type regions and the guard ring.