Recessed gate GaN MESFETs fabricated by the photoelectrochemical etching process


A new photo-electrochemical etching method was developed and used to fabricate GaN MESFETs. The etching process uses photoresist for masking illumination and the etchant is KOH based. The etching rate with 1.0 mol% of KOH for n-GaN is as high as 1600 Å/min under the Hg illumination of 35 mW/cm/2. The MESFET saturates at VDS = 4 V and pinches off at VGS = −3 V. The maximum drain current of the device is 230 mA/mmn at 300 K and the value is remained almost same for 500 K operation. The characteristic frequencies, fT and fmax, are 6.35 GHz and 10.25 GHz, respectively. Insensitivity of the device performance to temperature was attributed to the defect-related high activation energy of dopants for ionization and band-bending at the subgrain boundaries in GaN thin films.

This is a preview of subscription content, access via your institution.


  1. 1.

    R. J. Trew and M. W. Shin, Int. J. High Speed Electronics and Systems, 6, 211 (1995).

    Article  Google Scholar 

  2. 2.

    M. S. Shur, A. Khan, B. Gelmont, R. J. Trew, and M. W. Shin, Ins. Phys. Conf. Series No. 141: Chapter 4, 419 (1994).

    Google Scholar 

  3. 3.

    M. E. Lin, Z. F. Fan, Z. Ma, L. H. Allen, and H. Morcoc, Appl. Phys. Lett. 64, 887 (1994).

    CAS  Article  Google Scholar 

  4. 4.

    R. J. Shul, G. B. Aclellan, S. A. Casalnuovo, D. J. Reiger, S. J. Pearton, C. Constantine, C. Barrat, R. F. Karlicek. C. Tran, and M. Schurman, Appl. Phys. Lett., 69, 1119 (1996).

    CAS  Article  Google Scholar 

  5. 5.

    J. R. Milehan, S. J. Pearton, C. R. Abemathy, J. D. Mackenzie, R. J. Shul, and S. P. Kilcoyene, J. Vac. Sci. Technol., A. 14, 836 (1996).

    Article  Google Scholar 

  6. 6.

    M. W. Shin, R. J. Trew, and G. L. Bilbro, IEEE Electron Device Lett., 15, 292 (1994).

    CAS  Article  Google Scholar 

  7. 7.

    M. W. Shin, R. J. Trew, G. L. Bilbro, D. L. Dreifus, and A. J. Tessmer, J. Mater. Sci., 6, 111 (1995).

    CAS  Google Scholar 

  8. 8.

    F. A. Fonce, MRS Bulletin, 22, 51 (1997).

    Google Scholar 

  9. 9.

    Y. Park, B. Kim, I. Kim, and E. Oh, Proc. ’98 Korea-Japan Joint Workshop on SWSODM, 54 (1998).

Download references

Author information



Corresponding author

Correspondence to Won Sang Lee.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Lee, W.S., Choi, Y.H., Chung, K.W. et al. Recessed gate GaN MESFETs fabricated by the photoelectrochemical etching process. MRS Online Proceedings Library 572, 481 (1999).

Download citation