Facet Passivation of GaAs Based LDs by N2 Plasma Pretreatment and RF Sputtered AlxNy Film Coating

RF sputtered Al
_x
N
_y
thin film is deposited on the cavity surface of LD (laser diode) by N
₂
plasma pretreatment. Firstly optimize the preparation process of Al
_x
N
_y
film, and test the chemical ratio, reflectivity and optical absorption of the optimized Al
_x
N
_y
film by EDX, spectrophotometer and surface thermal lens technology respectively, which verify the feasibility of Al
_x
N
_y
used for facet coating film in LD process; then optimize the N
₂
plasma cleaning process, and use PL to find out that sputtered Al
_x
N
_y
passivation film by N
₂
plasma pretreatment can increase the GaAs surface photoluminescence efficiency by 119%. Finally, a 10 nm thick Al
_x
N
_y
passivation film is coated on cavity surface of LD with optimized N
₂
plasma pretreatment, which leads to a higher reliability than the traditional LD.