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| Testing device for wireless transmission towers |
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| Automotive audio system having active controls in reduced power state |
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| Radio communication apparatus and control method therefor |
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| Contact image sensor for use with a single ended power supply |
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| Quality-based handover |
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| Remotely programming a mobile terminal with a home location register address |
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| Image data transmission system and method |
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Compound semiconductor and controlled doping thereof
| Details |
Inventors: Larkin, David J.; Neudeck, Philip G.; Powell, J. Anthony; Matus, Lawrence G.;
Assignee: Ohio Aerospace Institute (Brook Park, OH)
Primary Examiner: Breneman; R. Bruce
Assistant Examiner: Fleck; Linda J.
Attorney, Agent or Firm: Vickers, Daniels & Young
A method of controlling the amount of impurity incorporation in a crystal grown by a chemical vapor deposition process. Conducted in a growth chamber, the method includes the controlling of the concentration of the crystal growing components in the growth chamber to affect the demand of particular growth sites within the growing crystal thereby controlling impurity incorporation into the growth sites. |
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DETAILED DESCRIPTION We claim: 1.
A method of controlling the amount of a selected element deposited in a given growth area of a crystal formed by Si and C as a SiC crystal is being grown at said area by a CVD process conducted in a growth chamber, wherein said Si is deposited in Si growth sites and said C is deposited in C growth sites, said element being competitive for one of said growth sites, said method comprising the steps of: a.
flowing a first amount of a gaseous Si compound through said chamber; b.
flowing a second amount of a gaseous C compound through said chamber; and c.
varying the ratio of said first and second amounts during the growing of said crystal to regulate said amount of said element deposited in said crystal at said area.
2.
A method as in claim 1, wherein said element competes for said C growth sites.
3.
A method as in claim 2, including the step of decreasing the rate of said element deposited in said C growth sites by decreasing said ratio of said first amount to said second amount.
4.
A method as in claim 2, including the step of increasing the rate of said element deposited in said C growth sites by increasing said ratio of said first amount to said second amount.
5.
A method as in claim 4, wherein said element is a dopant.
6.
A method as in claim 5, wherein said dopant is selected from a group consisting of phosphorous, nitrogen and boron.
7.
A method as in claim 1, wherein said element competes for said Si growth sites.
8.
A method as in claim 7, including the step of decreasing the rate of said element deposited in said Si growth sites by increasing said ratio of said first amount to said second amount.
9.
A method as in claim 7, including the step of increasing the rate of said element deposited in said Si growth sites by decreasing said ratio of said first amount to said second amount.
10.
A method as in claim 9, wherein said element is a dopant.
11.
A method as in claim 10, wherein said dopant is selected from a group consisting of aluminum and boron.
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