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Environmentally friendly method to grow wide-bandgap semiconductor aluminum nitride crystals: Elementary source vapor phase epitaxy.

Wu P, Funato M, Kawakami Y - Sci Rep (2015)

Bottom Line: Herein we propose a novel vapor-phase-epitaxy-based growth method for AlN that does not use toxic materials; the source precursors are elementary aluminum and nitrogen gas.This growth rate is comparable to that by HVPE, and the growth temperature is much lower than that in sublimation.Thus, this study opens up a novel route to achieve environmentally friendly growth of AlN.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic Science and Engineering, Kyoto University, Kyoto 615-8510, Japan.

ABSTRACT
Aluminum nitride (AlN) has attracted increasing interest as an optoelectronic material in the deep ultraviolet spectral range due to its wide bandgap of 6.0 eV (207 nm wavelength) at room temperature. Because AlN bulk single crystals are ideal device substrates for such applications, the crystal growth of bulky AlN has been extensively studied. Two growth methods seem especially promising: hydride vapor phase epitaxy (HVPE) and sublimation. However, the former requires hazardous gases such as hydrochloric acid and ammonia, while the latter needs extremely high growth temperatures around 2000 °C. Herein we propose a novel vapor-phase-epitaxy-based growth method for AlN that does not use toxic materials; the source precursors are elementary aluminum and nitrogen gas. To prepare our AlN, we constructed a new growth apparatus, which realizes growth of AlN single crystals at a rate of ~18 μm/h at 1550 °C using argon as the source transfer via the simple reaction Al + 1/2N2 → AlN. This growth rate is comparable to that by HVPE, and the growth temperature is much lower than that in sublimation. Thus, this study opens up a novel route to achieve environmentally friendly growth of AlN.

No MeSH data available.


Related in: MedlinePlus

Direct nitridation of the Al source metal by N2 gas.(a,b) Photographs of the Al source powder before nitridation and the product powder after nitridation, respectively. (c) Calculated XRD profile of AlN powder (upper) and experimental XRD profile of the nitrided powder (lower).
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f2: Direct nitridation of the Al source metal by N2 gas.(a,b) Photographs of the Al source powder before nitridation and the product powder after nitridation, respectively. (c) Calculated XRD profile of AlN powder (upper) and experimental XRD profile of the nitrided powder (lower).

Mentions: Before trying to grow an AlN single-crystal on a substrate, we confirmed the reactivity between Al and N2 by directly supplying N2 (instead of Ar) gas onto Al powders. Figure 2a,b how photographs of the Al source powder before nitridation and the product powder after nitridation, respectively. Nitridation was carried out at 1300 °C at 95 kPa for 1 hr.


Environmentally friendly method to grow wide-bandgap semiconductor aluminum nitride crystals: Elementary source vapor phase epitaxy.

Wu P, Funato M, Kawakami Y - Sci Rep (2015)

Direct nitridation of the Al source metal by N2 gas.(a,b) Photographs of the Al source powder before nitridation and the product powder after nitridation, respectively. (c) Calculated XRD profile of AlN powder (upper) and experimental XRD profile of the nitrided powder (lower).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663762&req=5

f2: Direct nitridation of the Al source metal by N2 gas.(a,b) Photographs of the Al source powder before nitridation and the product powder after nitridation, respectively. (c) Calculated XRD profile of AlN powder (upper) and experimental XRD profile of the nitrided powder (lower).
Mentions: Before trying to grow an AlN single-crystal on a substrate, we confirmed the reactivity between Al and N2 by directly supplying N2 (instead of Ar) gas onto Al powders. Figure 2a,b how photographs of the Al source powder before nitridation and the product powder after nitridation, respectively. Nitridation was carried out at 1300 °C at 95 kPa for 1 hr.

Bottom Line: Herein we propose a novel vapor-phase-epitaxy-based growth method for AlN that does not use toxic materials; the source precursors are elementary aluminum and nitrogen gas.This growth rate is comparable to that by HVPE, and the growth temperature is much lower than that in sublimation.Thus, this study opens up a novel route to achieve environmentally friendly growth of AlN.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic Science and Engineering, Kyoto University, Kyoto 615-8510, Japan.

ABSTRACT
Aluminum nitride (AlN) has attracted increasing interest as an optoelectronic material in the deep ultraviolet spectral range due to its wide bandgap of 6.0 eV (207 nm wavelength) at room temperature. Because AlN bulk single crystals are ideal device substrates for such applications, the crystal growth of bulky AlN has been extensively studied. Two growth methods seem especially promising: hydride vapor phase epitaxy (HVPE) and sublimation. However, the former requires hazardous gases such as hydrochloric acid and ammonia, while the latter needs extremely high growth temperatures around 2000 °C. Herein we propose a novel vapor-phase-epitaxy-based growth method for AlN that does not use toxic materials; the source precursors are elementary aluminum and nitrogen gas. To prepare our AlN, we constructed a new growth apparatus, which realizes growth of AlN single crystals at a rate of ~18 μm/h at 1550 °C using argon as the source transfer via the simple reaction Al + 1/2N2 → AlN. This growth rate is comparable to that by HVPE, and the growth temperature is much lower than that in sublimation. Thus, this study opens up a novel route to achieve environmentally friendly growth of AlN.

No MeSH data available.


Related in: MedlinePlus