A Schottky-Type Metal-Semiconductor-Metal Al0.24Ga0.76N UV Sensor Prepared by Using Selective Annealing

Asymmetric metal-semiconductor-metal (MSM) aluminum gallium nitride (AlGaN) UV sensors with 24% Al were fabricated using a selective annealing technique that dramatically reduced the dark current density and improved the ohmic behavior and performance compared to a non-annealed sensor. Its dark curr...

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Bibliographic Details
Published in:Sensors (Basel, Switzerland) Switzerland), 2021-06, Vol.21 (12), p.4243
Main Authors: Park, Byeong-Jun, Seol, Jeong-Hoon, Hahm, Sung-Ho
Format: Article
Language:English
Subjects:
Aluminum
aluminum gallium nitride (AlGaN)
Aluminum gallium nitrides
Annealing
Bias
Communication
Current density
Current leakage
Dark current
Electrodes
Gallium nitrides
Gold
Interdiffusion
local breakdown
Organic chemicals
Photoelectrons
Sensors
Spectrum analysis
Transmission electron microscopy
UV-to-visible rejection ratio (UVRR)
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Summary:Asymmetric metal-semiconductor-metal (MSM) aluminum gallium nitride (AlGaN) UV sensors with 24% Al were fabricated using a selective annealing technique that dramatically reduced the dark current density and improved the ohmic behavior and performance compared to a non-annealed sensor. Its dark current density at a bias of −2.0 V and UV-to-visible rejection ratio (UVRR) at a bias of −7.0 V were 8.5 × 10−10 A/cm2 and 672, respectively, which are significant improvements over a non-annealed sensor with a dark current density of 1.3 × 10−7 A/cm2 and UVRR of 84, respectively. The results of a transmission electron microscopy analysis demonstrate that the annealing process caused interdiffusion between the metal layers; the contact behavior between Ti/Al/Ni/Au and AlGaN changed from rectifying to ohmic behavior. The findings from an X-ray photoelectron spectroscopy analysis revealed that the O 1s binding energy peak intensity associated with Ga oxide, which causes current leakage from the AlGaN surface, decreased from around 846 to 598 counts/s after selective annealing.
ISSN:1424-8220
1424-8220
DOI:10.3390/s21124243