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Title [REGULAR PAPER] Selective Annealing Effects in Asymmetric Metal-semiconductor-metal AlGaN UV Sensors
Authors (Byeong-Jun Park) ; (Jeong-Hoon Seol) ; (Sung-Ho Hahm)
Page pp.510-517
ISSN 1598-1657
Keywords AlGaN sensors; UV-to-visible rejection ratio; ultraviolet; local breakdown; Al composition
Abstract Asymmetric metal-semiconductor-metal (MSM) AlGaN ultraviolet (UV) sensors with 33 % and 39 % Al composition were fabricated using the selective annealing method. Diodes with lower Al compositions exhibited lower dark current densities and improved UV sensing properties. TEM-EDS analysis showed that the selective annealing caused interdiffusion between the metals; the interface was modified by N penetration into the Ti layer. For UV sensors with Al composition of 33 %, the dark current density and the UV-to-visible rejection ratio (UVRR) after selective annealing were 7.7×10-10 A/cm2 and 135, respectively, which were significant improvements over the values of 1.9×10-8 A/cm2 and 19, respectively, before selective annealing. For UV sensors with Al composition of 39 %, the dark current density and UVRR were 2.3×10-6 A/cm2 and 45, respectively, after selective annealing, which were improved from the values of 6.4×10-6 A/cm2 and 11, respectively, before selective annealing.