Large area vertical Ga2O3 Schottky diodes for X-ray detection

Neil R. Taylor, Mihee Ji, Lei Pan, Praneeth Kandlakunta, Ivan Kravchenko, Pooran Joshi, Tolga Aytug, M. Parans Paranthaman, Lei R. Cao

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

The Schottky barrier diodes were fabricated from a bulk Sn-doped (001) n-type Ga2O3 substrate with a Si-doped epitaxial layer grown by hydride vapor phase epitaxy (HVPE), which demonstrate a good response to X-rays. Circular metal contacts with diameters ranging from 50 to 1500μm and square metal contacts ranging from 100×100μm2 to 1600×1600μm2 were deposited on the wafer. The devices were characterized for their electrical performance including forward current–voltage (FIV), reverse current–voltage (RIV), and capacitance–voltage (CV) measurements. The best device showed a breakdown voltage of −804 V and the devices tested had an average ideality of 1.12. The devices exhibited a clear response to X-rays even at zero bias with an experimentally observed response time ∼1.03 s and a linear response of detector signal to the X-ray dose rate. The experimentally observed device response time improved to ∼0.25 s when bias voltage is applied. The device also survived a long-term stability test of over 2 h under a constant X-ray irradiation. The sensitivity and the lower limit of detection for X-ray by Ga2O3 epitaxial Schottky detectors were discussed and determined as 43.5 μC/mGy cm−2 at −200 V and 8.31 nGyAir/s, respectively.

Funding

This material is based upon work partially supported by the US Department of Energy/National Nuclear Security Administration under Award Number(s) DE-NA0003921, by the Laboratory Directed Research and Development (LDRD), USA program of the Oak Ridge National Laboratory and by the US Department of Energy/Nuclear Energy University Program under Award Number DE-NE0008948. A portion of this research was conducted at the Center for Nanophase Materials Sciences, which is the US Department of Energy Office of Science User Facility. Neil Taylor is funded through the Consortium for Enabling Technologies and Innovation. This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. This material is based upon work partially supported by the US Department of Energy/National Nuclear Security Administration under Award Number(s) DE-NA0003921 , by the Laboratory Directed Research and Development (LDRD), USA program of the Oak Ridge National Laboratory and by the US Department of Energy/Nuclear Energy University Program under Award Number DE-NE0008948 . A portion of this research was conducted at the Center for Nanophase Materials Sciences, which is the US Department of Energy Office of Science User Facility. Neil Taylor is funded through the Consortium for Enabling Technologies and Innovation.

FundersFunder number
US Department of Energy/National Nuclear Security AdministrationDE-NA0003921
DOE Office of Nuclear EnergyDE-NE0008948
United States Government
U.S. Department of Energy
Oak Ridge National Laboratory
Laboratory Directed Research and Development

    Keywords

    • Gallium oxide (GaO)
    • Radiation detection
    • Schottky barrier diodes (SBDs)
    • Semiconductor devices
    • X-ray detection

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