| AVS 59th Annual International Symposium and Exhibition | |
| Electronic Materials and Processing | Tuesday Sessions |
| Session EM-TuM |
| Session: | Electrical Testing and Defects in III-V’s |
| Presenter: | R.V. Galatage, University of Texas at Dallas |
| Authors: | R.V. Galatage, University of Texas at Dallas D.M. Zhernokletov, University of Texas at Dallas H. Dong, University of Texas at Dallas B. Brennan, University of Texas at Dallas C.L. Hinkle, University of Texas at Dallas R.M. Wallace, University of Texas at Dallas E.M. Vogel, Georgia Institute of Technology |
| Correspondent: | Click to Email |
Anomalous frequency dispersion in accumulation is a commonly observed feature in experimental capacitance-voltage (C-V) characteristics of III-V metal-oxide-semiconductor (MOS) devices. Different models have been proposed to explain the origin of this frequency dispersion. One model attributes this dispersion to tunneling of the carriers into a disordered region caused by oxidation of the III-V substrate which is close to the interface between the III-V substrate and an insulator.1,2 Another model attributes this dispersion to border traps located inside the high-k dielectric.3,4 In this work, we use both HfO2 and Al2O3 with several interface treatments to differentiate between these two models.
MOS capacitors are fabricated on As-decapped n-In0.53G0.47As and n-GaAs substrates with either atomic layer deposited (ALD) HfO2 or Al2O3 dielectrics. An As-cap initially grown on the n-In0.53G0.47As surface to avoid spurious oxidation is thermally desorbed to leave a pristine surface. ALD HfO2 and Al2O3 is then deposited onto substrates prepared with several conditions: (1) in situ on the oxide free surface, (2) ex situ with a 10% ammonium sulfide and immediate transfer to ALD (<3 min exposure to air), (3) ex situ with a 10% ammonium sulfide treatment and ~30 min exposure to air prior to ALD. Companion GaAs samples receive similar ex situ ammonium sulfide treatments, air exposure times and ALD dielectrics for comparison. A detailed analysis of the effect of the different disordered region thicknesses and different dielectrics on the accumulation frequency dispersion and interface trap density (Dit) distribution will be presented. Correlation of electrical results to X-ray photoelectron spectroscopy (XPS) analysis will also be presented.
This work is sponsored by SRC FCRP Materials Structures and Devices Center and the National Science Foundation under ECCS Award No. 0925844.
1] H. Hasegawa and T. Sawada, IEEE Trans. Electron Devices 27(6), 1055 (1980).
[2] A. M. Sonnet, C. L. Hinkle, H. Dawei, G. Bersuker, and E. M. Vogel, IEEE Trans. Electron Devices, 57, 2599 (2010).
[3] Y. Yuan, L. Q. Wang, B. Yu, B. H. Shin, J. Ahn, P. C. McIntyre, P. M. Asbeck, M. J. W. Rodwell, and Y. Taur, IEEE Electron Device Lett.32 (4), 485 (2011).
[4] E. J. Kim, L. Wang, P. M. Asbeck, K. C. Saraswat, and P. C. McIntyre, Appl. Phys. Lett.96 (1), 012906 (2010).