GaAs Metal-Semiconductor Field-Effect Transistor에서 표면 결함이 소자의 전달컨덕턴스 분산 및 게이트 표면 누설 전류에 미치는 영향

Effects of Surface States on the Transconductance Dispersion and Gate Leakage Current in GaAs Metal - Semiconductor Field-Effect Transistor

  • 최경진 (포항공과대학교 신소재공학과) ;
  • 이종람 (포항공과대학교 신소재공학과)
  • Choe, Gyeong-Jin (Dept. of Materials Science and Engineering, Pohang University of Science and Technology) ;
  • Lee, Jong-Ram (Dept. of Materials Science and Engineering, Pohang University of Science and Technology)
  • 발행 : 2001.10.01

초록

CaAs metal semiconductor field effect transistor (MESFET) 소자의 전달컨덕턴스 분산 (transconductance dispersion) 현상과 게이트 누설 전류의 원인을 capacitance deep level transient spectroscopy (DLTS) 측정을 이용하여 해석하였다. DLTS 스펙트럼에서는 활성화 에너지가 각각 0.65×0.07 eV와 0.88 × 0.04 eV인 두개의 표면 결함과 0.84 × 0.01 eV의 활성화 에너지를 갖는 EL2를 관찰하였다. 전달컨덕턴스 분산 측정 결과, 전달컨덕턴스는 5.5 Hz ∼ 300 Hz의 주파수 영역에서 감소하였다. 전달컨덕턴스 분산을 온도의 함수로 측정한 결과, 온도가 증가할수록 전이 주파수는 증가하였고 전이 주파수의 온도 의존성으로부터 0.66 ∼ 0.02 eV의 활성화 에너지를 구할 수 있었다. 게이트 누설 전류 측정에서는 0.15 V 이하의 게이트 전압에서 순 방향과 역 방향 게이트 전압이 일치하는 오믹 전류-전압 특성을 나타내었고 게이트 누설 전류의 온도 의존성으로부터 구한 활성화 에너지는 0.63 ∼ 0.01 eV로 계산되었다. 서로 다른 방법으로 구한 활성화 에너지의 비교로부터 표면 결함 H1이 주파수에 따라서 감소하는 전달컨덕턴스 분산 및 게이트 누설 전류의 원인임을 알 수 있었다.

Origins for the transconductance dispersion and the gate leakage current in a GaAs metal semiconductor field effect transistor were found using capacitance deep-level transient spectroscopy (DLTS) measurements. In DLTS spectra, we observed two surface states with thermal activation energies of 0.65 $\times$ 0.07 eV and 0.88 $\times$ 0.04 eV and an electron trap EL2 with thermal activation energy of 0.84 $\times$ 0.01 eV. Transconductance was decreased in the frequency range of 5.5 Hz ~ 300 Hz. The transition frequency shifted to higher frequencies with the increase of temperature and the activation energy for the change of the transition frequency was determined to be 0.66 $\times$ 0.02 eV. From the measurements of the gate leakage current as a function of the device temperature, the forward and reverse currents are coincident with each other below gate voltages lower than 0.15 V, namely Ohmic behavior between gate and source/drain electrodes. The activation energy for the conductance of electrons on the surface of MESFET was 0.63 $\times$ 0.01 eV. Comparing activation energies obtained by different measurements, we found surface states H1 caused the transconductance dispersion and the fate leakage current.

키워드

참고문헌

  1. M. Ozeki, Kodama, M. Takikawa and A. Skibatomi, 'Analysis of electrical and optical properties of insulating film-GaAs interfaces using MESFET type sturctures,' J. Vac. Sci. Technol., vol.21, no. 2, pp. 437-441, 1982
  2. T. M. Barton and P. H. Ladbrooke, 'The role of device surface in high-voltage behavior of the GaAs MESFET's,' Solid State Electron., vol. 29, no. 8, pp. 807-813, 1986 https://doi.org/10.1016/0038-1101(86)90183-8
  3. J. Graffeuil, Z. Hadjoub, J. P. Fortea, and M. Pouysegur, 'Analysis of capacitance and transconductance frequency dispersion in MESFET's for surface characterization,' Solid State Electron., vol. 29, no. 10, pp. 1087-1097, 1986 https://doi.org/10.1016/0038-1101(86)90110-3
  4. M. Ozeki, K. Kodama, and A. Shibatomi, 'Surface analysis in GaAs MESFET's by gm frequency measurement,' Inst. Cong. Ser. no. 63. pp. 323-328
  5. P. H. Ladbrooke and S. R. Blight, Low-field low-frequency dispersion of transconductance in GaAs MESFET's with implications for other rate-dependent anomalies, IEEE Trans. Electron Devices, vol. ED-35, no. 3, pp. 257-267, 1988 https://doi.org/10.1109/16.2449
  6. G. Meneghesso, A. Paccagnella, D. V. Camin, N. Fedyakin, G. Pessina, and C. Canali, Study of Neutron Damage in GaAs MESFETs, IEEE Trans. Nuclear Science vol. 44, no. 3, pp. 840-846, 1997 https://doi.org/10.1109/23.603762
  7. Y. Y. Shan, C. C. Ling, A. H. Deng, B. K. Panda, C. D. Beling, and S. Fung, EL2 deep-level transient study in semi-insulating GaAs using positron-lifetime spectroscopy, Phys. Rev. B, vol. 55, no. 12, pp. 7624-7628, 1997 https://doi.org/10.1103/PhysRevB.55.7624
  8. S. R. Blight, R. H. Wallis, and H. Thomas, 'Surface influence on the conductance DLTS spectra of GaAs MESFET's,' IEEE Trans. Electron Devices, vol. ED-33, pp. 1447-1453, 1986
  9. J. H. Zhao, 'Modeling the effects of surface states on DLTS spectra of GaAs MESFET's,' IEEE Trans. Electron Devices, vol. 37, pp. 1235-1244, 1990 https://doi.org/10.1109/16.108184
  10. J. P. Harrang, A. Tardella, M. Rosso, P. Alnot, and J F. Peray, Conductance transient spectroscopy of metal-semiconductor field effect transistors, J. Appl. Phys., vol. 61, no. 5, pp. 1931-1936, 1987 https://doi.org/10.1063/1.338040
  11. T. M. Barton and P. H. Ladbrooke, The role of device surface in the high voltage behavior of the GaAs MESFET, Solid State Electron. vol. 29, no. 8, pp. 807-813, 1986 https://doi.org/10.1016/0038-1101(86)90183-8
  12. A. Paccagnella, C. Tedesco, C. Canali, A. Cetronio and C. Lanzieri, 'Frequency dispersion of transconductance : A tool to characterise deep levels in III-V FETs,' Electron. Lett. vol. 28, no. 22, 1992 https://doi.org/10.1049/el:19921351
  13. V. R. Balakrishnan, V. Kumar and S. Ghosh, Experimental evidence of surface conduction contributing to transconductance dispersion in GaAs MESFET's, IEEE Trans. Electron Devices, vol. 44, no. 7, pp. 1060-1065, 1997 https://doi.org/10.1109/16.595932