US20030145784A1
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US
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Cubic (zinc-blende) aluminum nitride and method of making same
Assignee: Individual
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Filing: 2003-02-10
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Granted: —
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Expires: 2023-02-10
Abstract
Abstract Device quality, single crystal film of cubic zinc-blende aluminum nitride (AlN) is deposited on a cubic substrate, such as a silicon (100) wafer by plasma source molecular beam epitaxy (PSMBE). The metastable zinc-blende form of AlN is deposited on the substrate at a low temperature by a low energy plasma beam of high-energy activated aluminum ions and nitrogen ion species produced in a molecular beam epitaxy system by applying a pulsed d.c. power to a hollow cathode source. In this manner, films having a thickness of at least 800 Å were produced. The lattice parameter of as-deposited films was calculated to be approximately 4.373 Å which corresponds closely to the theoretical calculation (4.38 Å) for cubic zinc-blende AlN. An interfacial layer of silicon carbide, specifically the cubic 3C—SiC polytype, interposed between the epitaxial film of zinc-blende AlN and the Si(100) wafer provides a template for growth and a good lattice match. The epitaxial layer of zinc-blende AlN has been characterized for its physical and optical properties. As a result, experimental data confirmed that zinc-blende AlN is an indirect semiconductor and has a bandgap about 5.34 eV. Due to the extraordinary piezoelectric properties of zinc-blende AlN, an illustrative device embodiment is a surface acoustic wave (SAW) device comprising interdigitated electrodes deposited by conventional means on the surface of the epitaxial layer of zinc-blende AlN to convert an electrical signal to a surface acoustic wave and vice versa.
Inventors
- 👤 Margarita Thompson
- 👤 Gregory Auner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:12
CPC Classifications
C; C30; C30B; C30B23/00; C30B23/02; C30B29/00; C30B29/10; C30B29/40; C30B29/403; H; H10; H10D; H10D62/00; H10D62/80; H10D62/85; H10D62/8503; H10N; H10N30/00; H10N30/01; H10N30/07; H10N30/074; H10N30/076; Y; Y10; Y10T; Y10T117/00; Y10T117/10
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
19 words
1 . A device-quality, single crystal film of cubic zinc-blende AlN having a thickness of at least 800 Å.
Claim 2
Dependent Claim
19 words
1 . A device-quality, single crystal film of cubic zinc-blende AlN having a thickness of at least 800 Å.
Claim 3
Dependent Claim
20 words
2 . The film of claim 1 wherein the cubic zinc-blende AlN has a lattice parameter of approximately 4.373 Å.
Claim 4
Dependent Claim
36 words
3 . A semiconductor device comprising: a substrate; and a layer of epitaxial zinc-blende AlN on a face surface of the substrate, the layer of epitaxial zinc-blend AlN having a thickness of at least 800 Å.
Claim 5
Dependent Claim
36 words
3 . A semiconductor device comprising: a substrate; and a layer of epitaxial zinc-blende AlN on a face surface of the substrate, the layer of epitaxial zinc-blend AlN having a thickness of at least 800 Å.
Claim 6
Dependent Claim
18 words
4 . The semiconductor device of claim 3 wherein the substrate has cubic symmetry on its growth surface.
Claim 7
Dependent Claim
24 words
5 . The semiconductor device of claim 4 wherein the substrate is selected from the group consisting of Si(100), MgO(100), 3C—SiC and combinations thereof.
Claim 8
Dependent Claim
20 words
6 . The semiconductor device of claim 4 wherein the cubic substrate is Si(100) with a surface layer of 3C—SiC.
Claim 9
Dependent Claim
41 words
7 . A semiconductor device comprising: a Si(100) substrate; a layer of 3C—SiC on a first surface of the Si(100) substrate; and a film of single crystal epitaxial zinc-blende AlN on the layer of 3C—SiC, oriented epitaxial to the (100) plane.
Claim 10
Dependent Claim
41 words
7 . A semiconductor device comprising: a Si(100) substrate; a layer of 3C—SiC on a first surface of the Si(100) substrate; and a film of single crystal epitaxial zinc-blende AlN on the layer of 3C—SiC, oriented epitaxial to the (100) plane.
Claim 11
Dependent Claim
35 words
8 . The semiconductor device of claim 7 wherein the zinc-blende AlN has a thickness of at least 800 Å, and preferably is in the range of at least about 1000 Å to 2000 Å.
Claim 12
Dependent Claim
56 words
9 . A surface acoustic wave device comprising: a substrate; an epitaxial layer of cubic zinc-blende AlN deposited on the substrate; and electrodes on the surface of the epitaxial layer of cubic zinc-blende AlN for converting an electrical signal to a surface acoustic wave and for converting the generated surface acoustic wave into an electrical signal.
Claim 13
Dependent Claim
56 words
9 . A surface acoustic wave device comprising: a substrate; an epitaxial layer of cubic zinc-blende AlN deposited on the substrate; and electrodes on the surface of the epitaxial layer of cubic zinc-blende AlN for converting an electrical signal to a surface acoustic wave and for converting the generated surface acoustic wave into an electrical signal.
Claim 14
Dependent Claim
21 words
10 . The surface acoustic wave device of claim 9 wherein the substrate has a cubic symmetry on its growth surface.
Claim 15
Dependent Claim
22 words
11 . The surface acoustic wave device of claim 10 wherein the substrate is Si(100) with a layer of cubic 3C—SiC thereon.
Claim 16
Dependent Claim
80 words
12 . A method of preparing a single crystal, epitaxial AlN film on a substrate comprising the steps of: a) forming a plasma of high energy activated aluminum ions and activated nitrogen ion species by the application of pulsed d.c. power to a source of aluminum and nitrogen; b) exposing the substrate to a low energy flux of the plasma; and c) growing an epitaxial AlN film on the substrate at a temperature in the range of 300° C.-800° C.
Claim 17
Dependent Claim
80 words
12 . A method of preparing a single crystal, epitaxial AlN film on a substrate comprising the steps of: a) forming a plasma of high energy activated aluminum ions and activated nitrogen ion species by the application of pulsed d.c. power to a source of aluminum and nitrogen; b) exposing the substrate to a low energy flux of the plasma; and c) growing an epitaxial AlN film on the substrate at a temperature in the range of 300° C.-800° C.
Claim 18
Dependent Claim
17 words
13 . The method of claim 12 wherein the pulsed r.f. power is between about 100 W-300W.
Claim 19
Dependent Claim
22 words
14 . The method of claim 12 further including the step of providing an acceleration bias to the surface of the substrate.
Claim 20
Dependent Claim
22 words
15 . The method of claim 12 wherein the substrate is pre-treated by subjecting the substrate to solvents to de-grease the substrate.
Claim 21
Dependent Claim
21 words
16 . The method of claim 15 further comprising the step of removing oxidation from the surface of the pre-treated substrate.
Claim 22
Dependent Claim
24 words
17 . The method of claim 16 wherein the step of removing oxidation comprises etching the surface of the pre-treated substrate with an acid.
Claim 23
Dependent Claim
31 words
18 . The method of claim 16 comprising the further step of pre-heating the substrate to a relatively high temperature for a period of time prior to said step of exposing.
Claim 24
Dependent Claim
42 words
19 . The method of claim 12 wherein the substrate is silicon and further comprises the step of subjecting the substrate to a source of carbon for creating a layer of cubic 3C—SiC on the silicon substrate upon the application of heat.
Claim 25
Dependent Claim
24 words
20 . The method of claim 12 further including the step of exposing the epitaxial film to a source of donor or acceptor electrons.
Claim 26
Dependent Claim
146 words
21 . A device for selectably depositing wurtzite or zinc-blende epitaxial films of Group III-V semiconductors on a substrate: a) a growth chamber; b) a substrate holder mounted in the growth chamber; c) a substrate bias power supply electrically connected to the substrate holder; d) an ultrahigh vacuum pump connected to the growth chamber; e) a heat source for the substrate; f) at least one plasma deposition source of high-energy target material within the growth chamber, the plasma deposition source comprising a magnetically-enhanced hollow cathode lined with target material; g) a source for supplying gaseous nitrogen and argon into the plasma deposition source; and h) a source of pulsed d.c. or r.f power electrically connected to the hollow cathode source for creating a plasma of high-energy aluminum, nitrogen, and argon species directed to impinge upon a growth surface of a substrate mounted to the substrate holder.
Claim 27
Dependent Claim
146 words
21 . A device for selectably depositing wurtzite or zinc-blende epitaxial films of Group III-V semiconductors on a substrate: a) a growth chamber; b) a substrate holder mounted in the growth chamber; c) a substrate bias power supply electrically connected to the substrate holder; d) an ultrahigh vacuum pump connected to the growth chamber; e) a heat source for the substrate; f) at least one plasma deposition source of high-energy target material within the growth chamber, the plasma deposition source comprising a magnetically-enhanced hollow cathode lined with target material; g) a source for supplying gaseous nitrogen and argon into the plasma deposition source; and h) a source of pulsed d.c. or r.f power electrically connected to the hollow cathode source for creating a plasma of high-energy aluminum, nitrogen, and argon species directed to impinge upon a growth surface of a substrate mounted to the substrate holder.
Claim 28
Dependent Claim
22 words
22 . The device of claim 21 further comprising an impeller in the plasma deposition source for ejecting plasma from the source.
Claim 29
Dependent Claim
161 words
23 . The device of claim 21 wherein the plasma deposition source comprises: a) a cathode comprising a hollow generally cylindrical chamber, the chamber having an opening at the upper end for emitting plasma and an inlet at the lower end for the gaseous components; b) magnetic field generating means surrounding the interior surface of the chamber to confine generated plasma by magnetic field; c) source target material lining the interior of the generally cylindrical chamber, the thickness of the source material increasing from the lower end of the chamber to the upper end of the chamber to provide a taper that further confines the plasma to the interior of the cylindrical chamber; d) an impeller rotatably mounted at the lower end of the chamber; e) a source of pulsed d.c. or r.f power electrically connected to the cathode; f) an anode surrounding the cathode; g) an insulating gap between the anode and cathode; and h) cooling means for the source.
References Cited (Backward Citations)
US5270263A
Cited
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