Claims
- 1. A method of preparing a thinned charge-coupled imaging device, comprising the steps of:
- providing a charge-coupled imaging device having a back surface and a gate structure formed on a front surface;
- implanting dopant ions of a selected element into the back surface using an ion beam energy of at least 100 keV to form a buried region of concentrated dopant atoms having a sharp implant distribution profile; and
- removing silicon from the back surface until a maximum dopant ion concentration is established in the device substantially at the back surface.
- 2. A method as described in claim 1, wherein the ion beam energy is in the range of 100-150 keV.
- 3. A method as described in claim 1, wherein the ions are implanted using an ion beam angle of approximately 7.degree..
- 4. A method as described in claim 1, wherein the selected element is boron.
- 5. A method as described in claim 4, wherein the boron concentration is established in a range between 1.times.10.sup.19 -1.times.19.sup.20 boron atoms per cubic centimeter of silicon.
- 6. A method as described in claim 1, additionally comprising the step of incorporating the dopant ions into the silicon matrix using laser activation.
- 7. A method as described in claim 4, wherein the laser activation is achieved using a laser at approximately 248 nm wavelength and a beam energy at the silicon surface of between 400 and 700 mJ/cm.sup.2.
- 8. A method as described in claim 1, wherein the step of removing silicon is achieved by polishing the back surface using a colloidal silica abrasive.
- 9. A method as described in claim 8, wherein the polishing step removes silicon at a rate of approximately 0.05 um/minute.
Parent Case Info
This is a continuation application of Ser. No. 249,401, now abandoned filed May 26, 1994, which is a division of application Ser. No. 07/906,624, U.S. Pat. No. 5,362,978 filed Jun. 30, 1992, which is a continuation of Ser. No. 670,762 filed Mar. 18, 1991 and now abandoned.
US Referenced Citations (8)
Divisions (1)
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Date |
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906624 |
Jun 1992 |
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Continuations (2)
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249401 |
May 1994 |
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670762 |
Mar 1991 |
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