US3839084A — Molecular beam epitaxy method for fabricating mag…

Claim 1

Independent Claim 178 words

A METHOD FOR EPTIAXIALLY GROWING UPON A SURFACE A P-TYPE THIN FILM OF A MATERIAL HAVING A COMPOSITION AIXB1-XC, WHERE 0<X$ 1, AL IS ALUMINUM, B IS A GROUP III(A) ELEMENT AND C IS A GROUP V(A) ELEMENT, COMPRISING THE STEPS OF: A. REDUCING THE BACKGROUND PRESSURE TO A SUBATMOSPHERIC PRESSURE; B. DIRECTING AT LEAST ONE MOLECULAR BEAM COMPRISING A P-TYPE DOPANT, SAID ALUMINUM, SAID GROUP III(A) ELEMENT AND SAID GROUP V(A) ELEMENT, UPON SAID SURFACE FOR A TIME PERIOD SUFFICIENT TO EFFECT GROWTH OF A P-TYPE FILM OF ALXB1-XC, 0 < X $ 1, OF THICKNESS; C. PREHEATING SAID SURFACE TO A TEMPERATURE EFFECTIVE TO ALLOW ATOMS IMPINGING THEREON TO MIGRATE TO SURFACE SITES TO FORM SAID EPITAXIAL FILM AND EFFECTIVE TO PRODUCE CONGRUENT EVAPORATION OF SAID GROUP III(A) ELEMENTS AND SAID GROUP V(A0 ELEMENT: D. MAINTAINING THE RELATIVE PROPORTIONS OF THE CONSTITUENTS OF SAID AT LEAST ONE MOLECULAR BEAM SO THAT AT SAID SURFACE THERE IS AN EXCESS OF SAID GROUP V(A) ELEMENT WITH RESPECT TO ALUMINUM AND SAID GROUP III(A) ELEMENT, AND CHARACTERIZED IN THAT:

Claim 2

Independent Claim 178 words

A METHOD FOR EPTIAXIALLY GROWING UPON A SURFACE A P-TYPE THIN FILM OF A MATERIAL HAVING A COMPOSITION AIXB1-XC, WHERE 0<X$ 1, AL IS ALUMINUM, B IS A GROUP III(A) ELEMENT AND C IS A GROUP V(A) ELEMENT, COMPRISING THE STEPS OF: A. REDUCING THE BACKGROUND PRESSURE TO A SUBATMOSPHERIC PRESSURE; B. DIRECTING AT LEAST ONE MOLECULAR BEAM COMPRISING A P-TYPE DOPANT, SAID ALUMINUM, SAID GROUP III(A) ELEMENT AND SAID GROUP V(A) ELEMENT, UPON SAID SURFACE FOR A TIME PERIOD SUFFICIENT TO EFFECT GROWTH OF A P-TYPE FILM OF ALXB1-XC, 0 < X $ 1, OF THICKNESS; C. PREHEATING SAID SURFACE TO A TEMPERATURE EFFECTIVE TO ALLOW ATOMS IMPINGING THEREON TO MIGRATE TO SURFACE SITES TO FORM SAID EPITAXIAL FILM AND EFFECTIVE TO PRODUCE CONGRUENT EVAPORATION OF SAID GROUP III(A) ELEMENTS AND SAID GROUP V(A0 ELEMENT: D. MAINTAINING THE RELATIVE PROPORTIONS OF THE CONSTITUENTS OF SAID AT LEAST ONE MOLECULAR BEAM SO THAT AT SAID SURFACE THERE IS AN EXCESS OF SAID GROUP V(A) ELEMENT WITH RESPECT TO ALUMINUM AND SAID GROUP III(A) ELEMENT, AND CHARACTERIZED IN THAT:

Claim 3

Dependent Claim 5 words

SAID P-TYPE DOPANT IS MAGNESIUM;

Claim 4

Dependent Claim 5 words

SAID P-TYPE DOPANT IS MAGNESIUM;

Claim 5

Dependent Claim 34 words

the sticking coefficient of magnesium on said surface, and hence the carrier concentration of said thin film, increases in accordance with a determinable relationship with increasing amounts of aluminum in said thin film; and

Claim 6

Dependent Claim 34 words

the sticking coefficient of magnesium on said surface, and hence the carrier concentration of said thin film, increases in accordance with a determinable relationship with increasing amounts of aluminum in said thin film; and

Claim 7

Dependent Claim 34 words

THE STICKING COEFFICIENT OF MAGNESIUM ON SAID SURFACE, AND HENCE THE CARRIER CONCENTRATION OF SAID THIN FFILM, INCREASES IN ACCORDANCE WITH A DETERMINABLE RELATIONSHIP WITH INCREASING AMOUNTS OF ALUMINUM IN SAID THIN FILM; AND

Claim 8

Dependent Claim 34 words

THE STICKING COEFFICIENT OF MAGNESIUM ON SAID SURFACE, AND HENCE THE CARRIER CONCENTRATION OF SAID THIN FFILM, INCREASES IN ACCORDANCE WITH A DETERMINABLE RELATIONSHIP WITH INCREASING AMOUNTS OF ALUMINUM IN SAID THIN FILM; AND

Claim 9

Dependent Claim 17 words

The method of claim 1 wherein said background pressure is reduced to at least 10 8 Torr.

Claim 10

Dependent Claim 28 words

aluminum is included in said at least one molecular beam in an amount determined from said relationship effective to produce a desired carrier concentration in said thin film.

Claim 11

Dependent Claim 28 words

aluminum is included in said at least one molecular beam in an amount determined from said relationship effective to produce a desired carrier concentration in said thin film.

Claim 12

Dependent Claim 80 words

The method of claim 1 wherein a first layer containing a first amount of Al is grown on said surface with the Mg flux in said at least one beam maintained at a first level, then a second layer containing a second amount of Al is grown, and during the growth of said second layer the Mg flux is changed to compensate for the change in the Mg sticking coefficient produced by the different amounts of Al in said layers.

Claim 13

Dependent Claim 28 words

ALUMINUM IS INCLUDED IN SAID AT LEAST ONE MOLECULAR BEAM IN AN AMOUNT DETERMINED FROM SAID RELATIONSHIP EFFECTIVE TO PRODUCE A DESIRED CARRIER CONCENTRATION IN SAID THIN FILM.

Claim 14

Dependent Claim 28 words

ALUMINUM IS INCLUDED IN SAID AT LEAST ONE MOLECULAR BEAM IN AN AMOUNT DETERMINED FROM SAID RELATIONSHIP EFFECTIVE TO PRODUCE A DESIRED CARRIER CONCENTRATION IN SAID THIN FILM.

Claim 15

Dependent Claim 22 words

The method of claim 1 wherein said surface is preheated to a temperature in the range of about 450* to 650* Centigrade.

Claim 16

Dependent Claim 23 words

The method of claim 4 wherein said thin film comprises a material selected from the group consisting of AlxGa1 xAs and AlxGa1 xP.

Claim 17

Dependent Claim 96 words

The method of claim 5 wherein said thin film comprises AlxGa1 xAs and said at least one molecular beam is formed by heating a first source of liquid Ga to produce a first beam of Ga molecules, by heating a second source of solid Al to produce a second beam of Al molecules, by heating a third source of As to produce a third beam of As molecules and by heating a fourth source of Mg to produce a fourth beam of Mg molecules, said first, second, third and fourth beams impinging simultaneously on said surface.

Claim 18

Dependent Claim 20 words

The method of claim 6 wherein said third source comprises polycrystalline GaAs to produce said third beam comprising As2 molecules.

Claim 19

Dependent Claim 64 words

The method of claim 6 wherein the sticking coefficienT of said Mg molecules on said surface increases according to said determinable relationship from about 10 5 to about 10 2 as the amount x of Al in said thin film increases from about 0 to 0.1 and produces a corresponding increase in the carrier concentration of said thin film from about 1016/cm3 to 1019/cm3.

Claim 20

Dependent Claim 44 words

The method of claim 6 wherein said thin film is made to have a carrier concentration greater than about 5 X 1017/cm3 by adapting the intensity of said aluminum beam to produce a thin film of AlxGa1 xAs with x greater than about 0.04.

Claim 21

Dependent Claim 21 words

The method of claim 9 wherein said second source of Al is heated to a temperature greater than about 1,270* K.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1977-09-30	1978-04-01	1978-10-01	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1981-09-30	1982-04-01	1982-10-01	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1985-09-30	1986-04-01	1986-10-01	$7700.00	Window Closed / Lapsed

Molecular beam epitaxy method for fabricating magnesium doped thin films of group iii(a)-v(a) compounds

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