Aluminium nitride

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Aluminium nitride
Aluminium Nitride powder
Wurtzite polyhedra.png
Other names
3D model (JSmol)
ECHA InfoCard 100.041.931 Edit this at Wikidata
EC Number
  • 246-140-8
RTECS number
  • BD1055000
  • InChI=1S/Al.N checkY
  • InChI=1/Al.N/rAlN/c1-2
  • [AlH2-]1[N+]47[AlH-]2[N+][AlH-]3[N+]8([AlH2-][NH+]([AlH2-]4)[AlH2-]6)[AlH-]4[N+][AlH-]5[N+]6([AlH2-]6)[Al-]78[N+]78[AlH-]([NH+]69)[NH+]5[AlH2-][NH+]4[AlH-]7[NH+]3[AlH2-][NH+]2[AlH-]8[NH+]1[AlH2-]9
  • [AlH2-]1[NH+]([AlH2-]6)[AlH2-][NH+]7[AlH-]2[N+][Al-]3([N+][AlH-]9[N+]5)[N+]18[Al-]45[N+][AlH-]5[NH+]6[Al-]78[N+]78[AlH2-][NH+]5[AlH2-][N+]4([AlH2-][NH+]9[AlH2-]4)[AlH-]7[N+]34[AlH2-][NH+]2[AlH2-]8
Molar mass 40.989 g/mol[1]
Appearance white to pale-yellow solid
Density 3.255 g/cm3[1]
Melting point 2,500 °C (4,530 °F; 2,770 K)[6]
hydrolyses (powder), insoluble (monocrystalline)
Solubility insoluble, subject of hydrolysis in water solutions of bases and acids [2]
Band gap 6.015 eV[3][4] (direct)
Electron mobility ~300 cm2/(V·s)
Thermal conductivity 321 W/(m·K)[5]
C6v4-P63mc, No. 186, hP4
a = 0.31117 nm, c = 0.49788 nm
30.1 J/(mol·K)
20.2 J/(mol·K)
−318.0 kJ/mol
−287.0 kJ/mol
GHS labelling:
GHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
H315, H319, H335, H373, H411
P260, P261, P264, P271, P280, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P321, P332+P313, P337+P313, P362, P363, P403+P233, P405, P501
NFPA 704 (fire diamond)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Aluminium nitride (AlN) is a solid nitride of aluminium. It has a high thermal conductivity of up to 321 W/(m·K)[5] and is an electrical insulator. Its wurtzite phase (w-AlN) has a band gap of ~6 eV at room temperature and has a potential application in optoelectronics operating at deep ultraviolet frequencies.

History and physical properties[edit]

AlN was first synthesized in 1862 by F. Briegleb and A. Geuther.[9][10]

AlN, in the pure (undoped) state has an electrical conductivity of 10−11–10−13 Ω−1⋅cm−1, rising to 10−5–10−6 Ω−1⋅cm−1 when doped.[11] Electrical breakdown occurs at a field of 1.2–1.8×105 V/mm (dielectric strength).[11]

The material exists primarily in the hexagonal wurtzite crystal structure, but also has a metastable cubic zincblende phase, which is synthesized primarily in the form of thin films. It is predicted that the cubic phase of AlN (zb-AlN) can exhibit superconductivity at high pressures.[12]

AlN has high thermal conductivity, high-quality MOCVD-grown AlN single crystal has an intrinsic thermal conductivity of 321 W/(m·K), consistent with a first-principle calculation.[5] For an electrically insulating ceramic, it is 70–210 W/(m·K) for polycrystalline material, and as high as 285 W/(m·K) for single crystals).[11]

Stability and chemical properties[edit]

Aluminium nitride is stable at high temperatures in inert atmospheres and melts at about 2200 °C. In a vacuum, AlN decomposes at ~1800 °C. In the air, surface oxidation occurs above 700 °C, and even at room temperature, surface oxide layers of 5–10 nm thickness have been detected. This oxide layer protects the material up to 1370 °C. Above this temperature bulk oxidation occurs. Aluminium nitride is stable in hydrogen and carbon-dioxide atmospheres up to 980 °C.[13]

The material dissolves slowly in mineral acids through grain-boundary attack and in strong alkalies through attack on the aluminium-nitride grains. The material hydrolyzes slowly in water. Aluminium nitride is resistant to attack from most molten salts, including chlorides and cryolite.[citation needed]

Aluminium nitride can be patterned with a Cl2-based reactive ion etch.[14][15]


AlN is synthesized by the carbothermal reduction of aluminium oxide in the presence of gaseous nitrogen or ammonia or by direct nitridation of aluminium. The use of sintering aids, such as Y2O3 or CaO, and hot pressing is required to produce a dense technical-grade material.


Epitaxially grown thin film crystalline aluminium nitride is used for surface acoustic wave sensors (SAWs) deposited on silicon wafers because of AlN's piezoelectric properties. One application is an RF filter, widely used in mobile phones,[16] which is called a thin-film bulk acoustic resonator (FBAR). This is a MEMS device that uses aluminium nitride sandwiched between two metal layers.[17]

AlN is also used to build piezoelectric micromachined ultrasound transducers, which emit and receive ultrasound and which can be used for in-air rangefinding over distances of up to a meter.[18][19]

Metallization methods are available to allow AlN to be used in electronics applications similar to those of alumina and beryllium oxide. AlN nanotubes as inorganic quasi-one-dimensional nanotubes, which are isoelectronic with carbon nanotubes, have been suggested as chemical sensors for toxic gases.[20][21]

Currently there is much research into developing light-emitting diodes to operate in the ultraviolet using gallium nitride based semiconductors and, using the alloy aluminium gallium nitride, wavelengths as short as 250 nm have been achieved. In 2006, an inefficient AlN LED emission at 210 nm was reported.[22]

Among the applications of AlN are

  • opto-electronics,
  • dielectric layers in optical storage media,
  • electronic substrates, chip carriers where high thermal conductivity is essential,
  • military applications,
  • as a crucible to grow crystals of gallium arsenide,
  • steel and semiconductor manufacturing.

See also[edit]


  1. ^ a b Haynes, p. 4.45.
  2. ^ Fukumoto, S.; Hookabe, T.; Tsubakino, H. (2010). "Hydrolysis behavior of aluminum nitride in various solutions". J. Mat. Science. 35 (11): 2743–2748. doi:10.1023/A:1004718329003. S2CID 91552821.
  3. ^ Haynes, p. 12.85.
  4. ^ Feneberg, M.; Leute, R. A. R.; Neuschl, B.; Thonke, K.; Bickermann, M. (2010). Phys. Rev. B. 82 (7): 075208. Bibcode:2010PhRvB..82g5208F. doi:10.1103/physrevb.82.075208.{{cite journal}}: CS1 maint: untitled periodical (link)
  5. ^ a b c Cheng, Zhe; Koh, Yee Rui; Mamun, Abdullah; Shi, Jingjing; Bai, Tingyu; Huynh, Kenny; Yates, Luke; Liu, Zeyu; Li, Ruiyang; Lee, Eungkyu; Liao, Michael E.; Wang, Yekan; Yu, Hsuan Ming; Kushimoto, Maki; Luo, Tengfei; Goorsky, Mark S.; Hopkins, Patrick E.; Amano, Hiroshi; Khan, Asif; Graham, Samuel (2020). "Experimental observation of high intrinsic thermal conductivity of AlN". Physical Review Materials. 4 (4): 044602. arXiv:1911.01595. Bibcode:2020PhRvM...4d4602C. doi:10.1103/PhysRevMaterials.4.044602. S2CID 207780348. Retrieved 2020-04-03.
  6. ^ Haynes, p. 12.80.
  7. ^ Vandamme, Nobuko S.; Richard, Sarah M.; Winzer, Stephen R. (1989). "Liquid-Phase Sintering of Aluminum Nitride by Europium Oxide Additives". Journal of the American Ceramic Society. 72 (8): 1409–1414. doi:10.1111/j.1151-2916.1989.tb07662.x.
  8. ^ Haynes, p. 5.4.
  9. ^ Fesenko I. P.; Prokopiv M. M.; Chasnyk V. I.; et al. (2015). Aluminium nitride based functional materials, prepared from nano/micron-sized powders via hot pressing/pressureless sintering. EPC ALCON. p. 11. ISBN 978-966-8449-53-6.
  10. ^ Briegleb, F.; Geuther, A. (1862). "Ueber das Stickstoffmagnesium und die Affinitäten des Stickgases zu Metallen". Justus Liebigs Annalen der Chemie. 123 (2): 228–241. doi:10.1002/jlac.18621230212.
  11. ^ a b c "AlN – Aluminium Nitride". Ioffe Database. Sankt-Peterburg: FTI im. A. F. Ioffe, RAN. Retrieved 2014-01-01.
  12. ^ Dancy, G. Selva; Sheeba, V. Benaline; Louis, C. Nirmala; Amalraj, A. (2015-09-30). "Superconductivity in Group III-V Semiconductor AlN Under High Pressure". Orbital - the Electronic Journal of Chemistry. Instituto de Quimica - Univ. Federal do Mato Grosso do Sul. 7 (3). doi:10.17807/orbital.v7i3.628. ISSN 1984-6428.
  13. ^ Berger, L. I. (1997). Semiconductor Materials. CRC Press. pp. 123–124. ISBN 978-0-8493-8912-2.
  14. ^ Chih-ming Lin; Ting-ta Yen; Yun-ju Lai; Felmetsger, V. V.; Hopcroft, M. A.; Kuypers, J. H.; Pisano, A. P. (March 2010). "Temperature-compensated aluminum nitride lamb wave resonators". IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control. 57 (3): 524–532. doi:10.1109/TUFFC.2010.1443. PMID 20211766. S2CID 20028149.
  15. ^ Xiong, Chi; Pernice, Wolfram H. P.; Sun, Xiankai; Schuck, Carsten; Fong, King Y.; Tang, Hong X. (2012). "Aluminum nitride as a new material for chip-scale optomechanics and nonlinear optics". New Journal of Physics. 14 (9): 095014. arXiv:1210.0975. Bibcode:2012NJPh...14i5014X. doi:10.1088/1367-2630/14/9/095014. ISSN 1367-2630. S2CID 118571039.
  16. ^ Tsuruoka, Doug (2014-03-17). "Apple, Samsung Cellphone Filter Orders Lift Avago". Investor's Business Daily.
  17. ^ "ACPF-7001: Agilent Technologies Announces FBAR Filter for U.S. PCS Band Mobile Phones and Data Cards". wirelessZONE. EN-Genius Network Ltd. 2002-05-27. Retrieved 2008-10-18.
  18. ^ "A Gestural Interface for Smart Watches".
  19. ^ Przybyla, R.; al, et (2014). "3D Ultrasonic Gesture Recognition". International Solid State Circuits Conference. San Francisco. pp. 210–211.
  20. ^ Ahmadi, A.; Hadipour, N. L.; Kamfiroozi, M.; Bagheri, Z. (2012). "Theoretical study of aluminium nitride nanotubes for chemical sensing of formaldehyde". Sensors and Actuators B: Chemical. 161 (1): 1025–1029. doi:10.1016/j.snb.2011.12.001.
  21. ^ Ahmadi Peyghan, A.; Omidvar, A.; Hadipour, N. L.; Bagheri, Z.; Kamfiroozi, M. (2012). "Can aluminum nitride nanotubes detect the toxic NH3 molecules?". Physica E. 44 (7–8): 1357–1360. Bibcode:2012PhyE...44.1357A. doi:10.1016/j.physe.2012.02.018.
  22. ^ Taniyasu, Y.; et al. (2006). "An Aluminium Nitride Light-Emitting Diode with a Wavelength of 210 Nanometres". Nature. 441 (7091): 325–328. Bibcode:2006Natur.441..325T. doi:10.1038/nature04760. PMID 16710416. S2CID 4373542.

Cited sources[edit]