Low Damage, High Anisotropy Inductively Coupled Plasma for Gallium Nitride based Devices
Name:
Youssef Ibrahim FInal Thesis.pdf
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Youssef Ibraham
Type
ThesisAuthors
Ibrahim, Youssef H.Advisors
Ooi, Boon S.
Committee Members
Foulds, Ian G.Kosel, Jürgen

Ooi, Boon S.

Program
Electrical EngineeringDate
2013-05-27Permanent link to this record
http://hdl.handle.net/10754/292971
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Show full item recordAbstract
Group III-nitride semiconductors possess unique properties, which make them versatile materials for suiting many applications. Structuring vertical and exceptionally smooth GaN profiles is crucial for efficient optical device operation. The processing requirements for laser devices and ridge waveguides are stringent as compared to LEDs and other electronic devices. Due to the strong bonding and chemically inert nature of GaN, dry etching becomes a critical fabrication step. The surface morphology and facet etch angle are analyzed using SEM and AFM measurements. The influence of different mask materials is also studied including Ni as well as a SiO2 and resist bilayer. The high selectivity Ni Mask is found to produce high sidewall angles ~79°. Processing parameters are optimized for both the mask material and GaN in order to achieve a highly anisotropic, smooth profile, without resorting to additional surface treatment steps. An optimizing a SF6/O2 plasma etch process resulted in smooth SiO2 mask sidewalls. The etch rate and GaN surface roughness dependence on the RF power was also examined. Under a low 2mTorr pressure, the RF and ICP power were optimized to 150W and 300W respectively, such that a smooth GaN morphology and sidewalls was achieved with reduced ion damage. The The AFM measurements of the etched GaN surface indicate a low RMS roughness ranging from 4.75 nm to 7.66 nm.ae974a485f413a2113503eed53cd6c53
10.25781/KAUST-QK33K