Improvement of passivation layer and Characterization of 850 nm Vertically cavity surface-emitting lasers

• Main Authors: Guo-Jhang Wu, 吳國彰
• Other Authors: Jenq-Yang Chang
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/45pb57

碩士 === 國立中央大學 === 光電科學與工程學系 === 107 === In this thesis, we use AlGaAs epitaxial wafer to fabricate 10GHz 850nm Vertical Cavity Surface Emitting Laser and increase modulation bandwidth by reducing parasitic capacitance. Reducing parasitic capacitance by isolation and two kind of passivation layers. The passivation layer is Benzocyclobutene (BCB) and Multilayer. First of all, Isolation reduces capacitance value in the same passivation layer. The capacitance value is reduced from 0.116 pF (W/O Isolation) to 0.069 pF (W/Isolation) in the BCB. The capacitance value is reduced from 0.145 pF (W/O Isolation) to 0.121 pF (W/Isolation) in the Multilayer×2. On the other hand, the passivation layer reduce capacitance value in the W/ Isolation. The capacitance value is reduced from 0.161 pF (Multilayer×1) to 0.121 pF (Multilayer×2) in the W/ Isolation. The capacitance value is reduced from 0.121 pF (Multilayer×2) to 0.069 pF (BCB) in the W/ Isolation. In the W/ Isolation, the modulation bandwidth is increase from 9.6 GHz (Multilayer×2) to 9.9 GHz (BCB). Although the Multilayer×2 and BCB has the similar threshold condition and modulation bandwidth, the advantages of the Multilayer×2 are good metal adhesion, simple process flow and low cost. Since the Multilayer×2 has similar element characteristics to BCB and improves the disadvantage of BCB, a thick composite film can replace BCB as a better passivation layer material.