Doping of IIB-VIA semiconductors during molecular beam epitaxy using neutral free radicals
AssigneeMinnesota Mining and Manufacturing Company
InventorsRobert M. Park, James M. DePuydt, Hwa Cheng, Michael A. Haase
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Abstract
A method and apparatus for enhanced doping of IIB-VIA semiconductors through the use of a free-radical source is described. The process involves the simultaneous production of beams of free-radicals together with group IIB molecules or atoms and group VIA molecules or atoms in a standard molecular beam epitaxy crystal growth system. These beams react on a substrate producing single crystal films of doped IIB-VIA semiconductors such as ZnSe:N, for example. The improved doping characteristics result from the high reactivity of radicals produced by the free-radical source with the surface of the growing crystal.
Claims46
A method of doping IIB-VIA semiconductors comprising the steps of:
- injecting a group IIB source into a molecular beam epitaxy chamber;
- injecting a group VIA source into the molecular beam epitaxy chamber;
- generating neutral free radicals using an rf plasma discharge free-radical source;
- injecting free-radicals into the molecular beam epitaxy chamber from the rf plasma discharge free radical source;
- and
- growing a IIB-VIA semiconductor layer, doped with free-radicals.
A method of producing an electromagnetic radiation transducer comprising:
- placing an n-type substrate in a molecular beam epitaxy growth chamber;
- growing an n-type semiconductor layer upon the n-type substrate;
- growing an IIB-VIA semiconductor layer upon the n-type semiconductor layer;
- and
- doping the IIB-VIA semiconductor layer p-type during the step of growing the IIB-VIA semiconductor layer by injecting neutral free-radicals generated using an rf plasma discharge free-radical source into the molecular beam epitaxy growth chamber.
A method of producing an electromagnetic radiati emitting transducer comprising:
- placing a p-type substrate in a molecular beam epitaxy growth chamber;
- growing a IIB-VIA semiconductor layer upon the p-type substrate;
- doping the IIB-VIA semiconductor layer p-type during the step of growing the IIB-VIA semiconductor layer by injecting neutral free-radicals generated using an rf plasma discharge free-radical radical source into the molecular beam epitaxy growth chamber;
- and
- growing an n-type semiconductor layer upon the IIB-VIA semiconductor layer.
A method of producing p-type ZnSe comprising:
- injecting a Zn source in a molecular beam epitaxy growth chamber;
- injecting a Se source into the molecular beam epitaxy growth chamber;
- generating neutral free radicals using an rf plasma discharge free-radical source;
- injecting free radicals generated using the rf plasma discharge free-radical source into the molecular beam epitaxy growth chamber;
- and
- growing a p-type ZnSe layer in the molecular beam epitaxy growth chamber, wherein the IIB-VIA semiconductor layer has a net donor to net acceptor ratio (N.sub.D /N.sub.A) of less than or equal to 0.8.
A method of doping IIB-VIA semiconductors comprising the steps of:
- injecting a group IIB source into a molecular beam epitaxy chamber;
- injecting a group VIA source into the molecular beam epitaxy chamber;
- generating neutral free radicals using an electron cyclotron resonance free-radical source;
- injecting free-radicals into the molecular beam epitaxy chamber from the electron cyclotron resonance free-radical source;
- and
- growing a IIB-VIA semiconductor layer, doped with free-radicals.
A method of producing an electromagnetic radiation transducer comprising:
- placing an n-type substrate in a molecular beam epitaxy growth chamber;
- growing an n-type semiconductor layer upon the n-type substrate;
- growing a IIB-VIA semiconductor layer upon the n-type semiconductor layer;
- and
- doping the IIB-VIA semiconductor layer p-type during the step of growing the IIB-VIA semiconductor layer by injecting neutral free-radicals generated using an electron cyclotron resonance free-radical source into the molecular beam epitaxy growth chamber.
The method of claim 56 wherein a growth rate for the IIB-VIA semiconductor layer ranges from about 0.4 .mu.m/h to about 2.0 .mu.m/h.
A method of producing an electromagnetic radiation emitting transducer comprising:
- placing a p-type substrate in a molecular beam epitaxy growth chamber;
- growing a IIB-VIA semiconductor layer upon the p-type substrate;
- doping the IIB-VIA semiconductor layer p-type during the step of growing the IIB-VIA semiconductor layer by injecting neutral free-radicals generated using an electron cyclotron resonance free-radical source into the molecular beam epitaxy growth chamber;
- and
- growing an n-type semiconductor layer upon the IIB-VIA semiconductor layer.
A method of producing p-type ZnSe comprising:
- injecting a Zn source in a molecular beam epitaxy growth chamber;
- injecting a Se source into the molecular beam epitaxy growth chamber;
- generating neutral free radicals using an electron cyclotron resonance free-radical source;
- injecting free radicals generated from the electron cyclotron resonance free-radicals source into the molecular beam epitaxy growth chamber;
- and
- growing a p-type ZnSe layer in the molecular beam epitaxy growth chamber.
A method of producing p-type ZnSe comprising:
- injecting a Zn source in a molecular beam epitaxy growth chamber;
- injecting a Se source into the molecular beam epitaxy growth chamber;
- generating neutral free radicals using a free-radical source;
- injecting neutral free radicals generated using the free-radical source into the molecular beam epitaxy growth chamber;
- growing a p-type ZnSe layer in the molecular beam epitaxy growth chamber;
- and
- wherein the neutral free radicals are of an energy level sufficiently low to yield a p-type ZnSe layer having a resistivity of less than 15 .OMEGA.-cm and a net acceptor concentration of more than 5.times.10.sup.15 cm.sup.-3.
Dependencies are inferred from the claim text.