Semiconductor SiCl light source and a method of manufacturing same

• US 3,986,193 A
• Filed: 06/13/1975
• Issued: 10/12/1976
• Est. Priority Date: 02/08/1973
• Status: Expired due to Term

• Current Assignee: Administratrix, By Irina Vladimirovna Valter-Maslakovets, Deceased, Jury Petrovich Maslakovets, Eduard Efimovich Violin, Evgeny Nikolaevich Mokhov, Galina Alexandrovna Lomakina, Georgy Fedorovich Kholuyanov, Igor Ivanovich Kruglov, Igor Veniaminovich Ryzhikov, Jury Alexandrovich Vodakov, Tatyana Georgievna Kmita, Vadim Ivanovich Pavlichenko
• Original Assignee: Administratrix, By Irina Vladimirovna Valter-Maslakovets, Deceased, Jury Petrovich Maslakovets, Eduard Efimovich Violin, Evgeny Nikolaevich Mokhov, Galina Alexandrovna Lomakina, Georgy Fedorovich Kholuyanov, Igor Ivanovich Kruglov, Igor Veniaminovich Ryzhikov, Jury Alexandrovich Vodakov, Tatyana Georgievna Kmita, Vadim Ivanovich Pavlichenko
• Inventors: Kruglov, Igor Ivanovich, Kmita, Tatyana Georgievna, Ryzhikov, Igor Veniaminovich, Mokhov, Evgeny Nikolaevich, Kholuyanov, Georgy Fedorovich, Valter-Maslakovets, administratrix, by Irina Vladimirovna, Vodakov, Jury Alexandrovich, Violin, Eduard Efimovich, Pavlichenko, Vadim Ivanovich, Maslakovets, deceased, Jury Petrovich, Lomakina, Galina Alexandrovna
• Primary Examiner(s): Edlow, Martin H.
• Application Number:
  US05/586,791
• Time in Patent Office: 487 Days
• Field of Search: 357/17, 357/63, 357/61, 357/18, 148/190
• US Class Current: 257/77
• CPC Class Codes: H01L 33/343 characterised by the doping materials
• CPC Class Codes: Y10S 438/931 Silicon carbide semiconductor

Abstract

A semiconductor light source using nitrogen-doped n-type silicon carbide with a p-n junction electroluminescent within the visible region of the spectrum, and with a p-layer doped with an acceptor impurity, wherein the uncompensated majority donor concentration in said silicon carbide is 0.8 × 10¹⁸ to 5 × 10¹⁸ cm.sup.^-3, the p-layer is doped with an acceptor impurity with a minimum activation energy and with a solubility in silicon carbide of about 10¹⁹ to 10²⁰ cm.sup.^-3, the uncompensated donor concentration in the base layer is 0.8 × 10¹⁸ to 5 × 10¹⁸ cm.sup.^-3 and a central layer, 0.05 to 1 micron thick, located between the p-layer and the base layer is doped with luminescence activators of donor and acceptor types to a concentration of 0.1 × 10¹⁸ to 2 × 10¹⁸ cm.sup.^-3 and has a resistivity greater than the resistivity of the base layer by at least three orders of magnitude.

Claims

1. A semiconductor light source comprising a silicon carbide crystal having a three-layer structure comprising:

an N-type conductivity base region doped with nitrogen and having a concentration of basic uncompensated donors varying from 0.8 ×

10¹⁸ to 5 ×

10¹⁸ cm.sup.^-3 ;

a P-type conductivity layer having a thickness of 0.05 to 1 micron, doped with an acceptor admixture having a minimal activation energy and solubility in said silicon carbide on the order of 2 ×

10¹⁸ to 2 ×

10²⁰ cm.sup.^-3, said P-type layer forming, together with said N-type region, a P-N junction;

an N-type conductivity layer of silicon carbide located between said P-type layer and said N-type conductivity base region and having a thickness of 0.05 to 1 micron and a resistivity of at least three orders of magnitude higher than the resistivity of said N-type conductivity base region, said N-type layer being doped with luminescence activators of donor and acceptor types of conductivity to a concentration of 0.1 ×

10¹⁸ to 2 ×

10¹⁸ cm.sup.^-3.

2. A semiconductor light source as of claim 1 wherein the luminescence activator of donor type is a substance selected from a group consisting of oxygen and nitrogen and the acceptor-type luminescence activator is boron.

3. A semiconductor light source as of claim 1 wherein the donor-type luminescence activators are nitrogen and oxygen and the acceptor-type luminescence activator is a substance selected from a group consisting of beryllium, aluminium, gallium and scandium.

4. A method of forming a semiconductor light source comprising:

a nitrogen-doped n-type silicon carbide crystal with an uncompensated majority donor concentration of 0.8 ×

10¹⁸ to 5 ×

10¹⁸ cm.sup.^-3 ;

a p-n junction formed by introducing an acceptor impurity which has a low activation energy and a high solubility in said silicon carbide, said junction being electroluminescent within the visible region of the spectrum;

a p-layer, 0.05 to 1 micron thick, doped with an acceptor impurity with a minimum activation energy and with a solubility in said silicon carbide of about 2 ×

10¹⁸ to 2 ×

10²⁰ cm.sup.^-3 ;

a base layer of silicon carbide which is part of said silicon carbide crystal and has an uncompensated donor concentration of 0.8 ×

10¹⁸ to 5 ×

10¹⁸ cm.sup.^-3 ;

a central layer located between said p-layer and said base layer and doped after formation of the p-n junction with luminescence activators of donor and acceptor types by adding the luminescence activators from the side from which impurities were introduced to form the p-n junction, to concentrations of 0.1 ×

10¹⁸ - 2 ×

10¹⁸ cm.sup.^-3 ;

said central layer is 0.05 to 1 micron thick and its resistivity is greater than the resistivity of said base layer by at least three orders of magnitude.

5. The method as of claim 4 wherein a p-n junction is formed by aluminium diffusion in an inert atmosphere into which vapours of rare-earth elements are introduced.

6. The method as of claim 5 wherein a p-n junction is formed by adding oxygen to the inert atmosphere.

7. A method of forming a semiconductor light source comprising:

a nitrogen doped n-type silicon carbide crystal with an uncompensated major donor concentration of 0.8 ×

10¹⁸ to 5 ×

10¹⁸ cm.sup.^-3 ;

a p-layer, 0.05 to 0.1 micron thick, doped with an acceptor impurity which has a minimum activation energy and a solubility in said silicon carbide of about 2 ×

10¹⁸ to 2 ×

10²⁰ cm.sup.^-3 ;

a base layer which is part of said silicon carbide crystal and has an uncompensated donor concentration of 0.8 ×

10¹⁸ to 5 ×

10¹⁸ cm.sup.^-3 ;

a central layer located between said p-layer and said base layer and doped with luminescence activators of donor and acceptor types to concentrations of 0.1 ×

10¹⁸ to 2 ×

10¹⁸ cm.sup.^-3 ;

a p-n junction formed after the doping of the central layer by adding an acceptor impurity with a low activation energy and a high solubility in said silicon carbide, said junction being electroluminescent within the visible region of the spectrum;

said central layer is 0.05 to 1 micron thick and its resistivity is greater than the resistivity of said base layer by at least three orders of magnitude.

8. The method as of claim 7 wherein a p-n junction is formed by aluminium diffusion in an inert atmosphere into which vapours of rare-earth elements are introduced.

9. The method as of claim 8 wherein a p-n junction is formed by adding oxygen to the inert atmosphere.

10. The method as of claim 7 wherein a luminescence activator of acceptor type is introduced by diffusion and a p-n junction is also formed by diffusion, the diffusion of the acceptor impurity with a low activation energy being carried out in an inert atmosphere with addition of a small amount of a luminescence activator.