Low resistance n-contact for UVC LEDs by a two-step plasma etching process

Hyun Kyong Cho, Ji-Hye Kang, Luca Sulmoni, Kevin Kunkel, Jens Rass, Norman Susilo, Tim Wernicke, Sven Einfeldt, Michael Kneissl
2020 Semiconductor Science and Technology  
The impact of plasma etching on the formation of low-resistance n-contacts on the AlGaN:Si current spreading layer during the chip fabrication of ultraviolet light-emitting diodes (UV LEDs) emitting at 265 nm is investigated. A two-step plasma etching process with a first rapid etching using BCl 3 /Cl 2 gas mixture and a second slow etching step using pure Cl 2 gas has been developed. The etching sequence provides smooth mesa side-walls and an n-AlGaN surface with reduced surface damage. Ohmic
more » ... -contacts with a contact resistivity of 3.5 × 10 −4 Ωcm 2 are obtained on Si-doped Al 0.65 Ga 0.35 N layers and the operating voltages of the UVC LEDs were reduced by 2 V for a current of 20 mA.
doi:10.1088/1361-6641/ab9ea7 fatcat:ytptxcj4qvg4jn42f7jw5fjjny