III-V Semiconductor Devices

ALD Applications

The Ultratech/CNT Fiji has been at the forefront of recent advances in III-V devices. This includes deposition of III-V materials like AlN, InN and GaN via atomic layer epitaxy (ALE), epitaxial growth of device quality ternary compounds like AlxGa1-xN and InlxAl1-xN, deposition of buffer layers to enable hetero-epitaxy and growth of gate dielectrics and passivation layers

ALD enabled III-V devices: Epitaxial growth, multicomponent films, passivation layers

Epitaxial growth of device quality AlN [2], InN [1] and GaN [3] has recently been demonstrated in an Ultratech/CNT Fiji. In Fig.1 below, HRTEM and IFFT confirms crystalline InN aligned with a-sapphire. Fig.2 shows the high quality of AlN grown on GaN – the FWHM of the rocking curve is 670 arc sec for a 37nm film – this is comparable to 1.6μm grown by MBE (420 arc sec) .

High Electron Mobility Transistor is based on formation of a high mobility 2D electron gas at interface between lattice-matched semiconductors. Table-1 shows low carrier concentration and high mobility in an all ALD HEMT device (ALE GaN/ALE AlGaN/ALD Al2O3) indicating the presence of the 2D electron gas. Additionally, HEMT device performance improvement has been shown [5] due to surface passivation by ALE-AlN. Hybrid graphene/III-N heterostructures have been grown [6] enabled by the low temperature of ALD which preserves the surface functionalization of graphene.

Sample μ (cm2/V-s) Ns (cm-2)
AlGaN / GaN 1042 1.6 x 1012
Al2O3 / Al0.27Ga0.73N / GaN 871 6.0 x 1011
Table-1: HEMT devices via ALD/ALE [4]

ALD Benefits for III-V Devices

Low deposition temperature

Ease of growth of alloys including phases not accessed previously

Deposition on 3D structures like nano-wires

Battery Microscopic Image

Figure 1: InN on sapphire [1]

Figure 2: Peaks from AlN/GaN/a-sapphire [2]

REFERENCES – Recent publications done on Ultratech CNT ALD platforms

  1. Nepal, N., Anderson, V. R., Hite, J. K. & Eddy, C. R., Jr. Growth and Characterization of III-N Ternary Thin Films by Plasma Assisted Atomic Layer Epitaxy at Low Temperatures. Thin Solid Films 1–17 (2015). doi:10.1016/j.tsf.2015.04.068
  2. Ozgit-Akgun, C. et al. Fabrication of flexible polymer–GaN core–shell nanofibers by the combination of electrospinning and hollow cathode plasma-assisted atomic layer deposition. J. Mater. Chem. C (2015). doi:10.1039/C5TC00343A
  3. Altuntas, H., Ozgit-Akgun, C., Donmez, I. & Biyikli, N. Current transport mechanisms in plasma-enhanced atomic layer deposited AlN thin films. J Appl Phys 117, 155101 (2015).
  4. OConnor, E. et al. Effect of forming gas annealing on the inversion response and minority carrier generation lifetime of n and p-In0.53Ga0.47As MOS capacitors. Microelectron Eng (2015). doi:10.1016/j.mee.2015.04.103
  5. Kao, E., Yang, C., Warren, R., Kozinda, A. & Lin, L. ALD titanium nitride coated carbon nanotube electrodes for electrochemical supercapacitors. TRANSDUCERS 2015 - 2015 18th International Solid-State Sensors, Actuators and Microsystems Conference 498–501 (2015). doi:10.1109/TRANSDUCERS.2015.7180969
  6. Haider, A., Ozgit-Akgun, C., Goldenberg, E., Okyay, A. K. & Biyikli, N. Low-Temperature Deposition of Hexagonal Boron Nitride Via Sequential Injection of Triethylboron and N 2/H 2Plasma. J Am Ceram Soc n/a–n/a (2014). doi:10.1111/jace.13213
  7. Assaud, L., Pitzschel, K., Hanbucken, M. & Santinacci, L. Highly-Conformal TiN Thin Films Grown by Thermal and Plasma-Enhanced Atomic Layer Deposition. ECS Journal of Solid State Science and Technology 3, P253–P258 (2014).
  8. Koehler, A. D., Nepal, N., Anderson, J. T., Hobart, K. D. & Kub, F. J. Investigation of AlGaN/GaN HEMTs Passivated by AlN Films Grown by Atomic Layer Epitaxy. in 135 (2013).
  9. Ozgit-Akgun, C., Donmez, I. & Biyikli, N. (Invited) Plasma-Enhanced Atomic Layer Deposition of III-Nitride Thin Films. ECS Transactions 58, 289–297 (2013).
  10. Eddy, C. R., Jr, Nepal, N., Hite, J. K. & Mastro, M. A. Perspectives on future directions in III-N semiconductor research. Journal Of Vacuum Science & Technology A-Vacuum Surfaces And Films 31, 058501 (2013).
  11. Nepal, N. et al. Epitaxial Growth of III–Nitride/Graphene Heterostructures for Electronic Devices. Appl Phys Express 6, 061003 (2013).
  12. Nepal, N. et al. Epitaxial Growth of Cubic and Hexagonal InN Thin Films via Plasma-Assisted Atomic Layer Epitaxy. Cryst Growth Des 13, 1485–1490 (2013).
  13. Ozgit-Akgun, C., Kayaci, F., Donmez, I., Uyar, T. & Biyikli, N. Template-Based Synthesis of Aluminum Nitride Hollow Nanofibers Via Plasma-Enhanced Atomic Layer Deposition. J Am Ceram Soc n/a–n/a (2012). doi:10.1111/jace.12030<
  14. Ozgit, C., Donmez, I., Alevli, M. & Biyikli, N. Atomic layer deposition of GaN at low temperatures. J Vac Sci Technol A 30, (2012).
  15. Biyikli, N., Ozgit, C. & Donmez, I. Low-Temperature Self-Limiting Growth of III-Nitride Thin Films by Plasma-Enhanced Atomic Layer Deposition. Nanosci Nanotechnol Lett 4, 1008–1014 (2012).
  16. Ozgit, C., Donmez, I., Alevli, M. & Biyikli, N. Atomic layer deposition of GaN at low temperatures. J Vac Sci Technol A 30, 01A124 (2012).
  17. Alevli, M., Ozgit, C., Donmez, I. & Biyikli, N. Structural properties of AlN films deposited by plasma-enhanced atomic layer deposition at different growth temperatures. phys. stat. sol. (a) 209, 266–271 (2011).
  18. Alevli, M., Ozgit, C., Donmez, I. & Biyikli, N. The influence of N2/H2 and ammonia N source materials on optical and structural properties of AlN films grown by plasma enhanced atomic layer deposition. J Cryst Growth 335, 51–57 (2011).
  19. Alevli, M., Ozgit, C. & Donmez, I. The Influence of Growth Temperature on the Properties of AlN Films Grown by Atomic Layer Deposition. ACTA PHYSICA POLONICA A (2011).
  20. Ozgit, C., Donmez, I. & Biyikli, N. Self-Limiting Growth of GaN at Low Temperatures. ACTA PHYSICA POLONICA A (2011).