GaN Dry Etching Process (RIE or ICP-RIE)

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Material Properties and Applications of Gallium Nitride (GaN)

Gallium Nitride (GaN) is a III-V compound semiconductor material which has wide band gap and high electron mobility.

• Band Gap : 3.4 eV (300 K, direct)
• Electron Mobility : 440 cm2/(V·s) (300 K)
• Thermal Conductivity : 1.3 W/(cm·K) (300 K)

Usually GaN layers are deposited using Metal Organic Chemical Vapor Deposition (MOCVD) or Molecular Beam Epitaxy (MBE). GaN can be deposited on several types of substrates such as Sapphire, Silicon or Silicon Carbide (SiC), but the cost of GaN epi process and repeatable high-quality crystal growth are challenges in GaN-based device fabrication.

Gallium Nitride in Periodic Table

GaN is an attractive material for following applications due to these unique material properties.

• Power Devices including the metal–oxide–semiconductor field-effect transistor (MOSFET) and the high-electron-mobility transistor (HEMT)
• High-brightness (HB) Light-emitting-diodes (LEDs)
• RF and microwave devices for telecommunication
• High-power blue laser diode

GaN/AlGaN Anisotropic Etching

Vertical and smooth sidewall without skirt was achieved using chlorine chemistry. There is no notches on the AlGaN bottom edge. Furthermore, there is no pillars on the entire surface.

Etch Rate : 142 nm/min
Etch Selectivity : 8.6 (over SiO2 mask)
Etch Uniformity : ±1.7 % (over the 2-inch substrate)

This highly anisotropic etch process is useful for blue laser diode fabrication.

Ridge Form Formation of GaN for blue laser diode
AlGaN GaN Etch for Blue Laser Diode
AlGaN GaN Etch without pillar

Any questions on our process capabilities on GaN etching?

GaN Reverse Tapered Etching

For improving the external luminance of GaN-based LEDs, light escaping via the GaN sidewalls needs to be prevented.
SAMCO developed a reverse-tapered etch process of GaN using chlorine chemistry.

GaN Anti Mesa Etching for GaN LED

Reverse-tapered Angle : 70°

GaN-Anti-Mesa-Etching for GaN LED

 Etch Rate : 140 nm/min (using a Ni mask)

GaN Reverse Taper Etch for LED

Reverse-tapered GaN layer on Patterned Sapphire Substrate (PSS)

Any questions on our process capabilities on GaN etching?

GaN Etching with Smooth Sidewalls

GaN films with a minimum level of crystal defects are essential for blue LED and laser diode applications. Epitaxial Lateral Overgrowth (ELO) is one method for depositing lower defect GaN films. Etching of GaN plays a critical role in GaN ELO. GaN was etched using a SiO2 mask. The etched profile showed smooth surface and sidewalls.

Etch rate : 0.3~0.4 µm/min

Photo courtesy of Hiramatsu Research Center, Department of Engineering, Mie University

GaN Etch with Smooth Sidewalls

System Lineup for GaN Dry Etching

RIE Systems

– Excellent GaN etch uniformity over the wafers
– Optional optical/Interferometric end-point detection
– Easy-to-use touch-panel GUI


RIE Systems for InP Plasma Etching

 

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ICP Etch Systems

– ICP plasma sources optimizing GaN etch profile control
– Optional optical/Interferometric end-point detection
– Easy-to-use touch-panel GUI


ICP Etch Systems for GaN Plasma Etching

 

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ICP Etch Systems for Batch Processing

– Process chambers accommodating multiple small wafers
– Optional optical/Interferometric end-point detection
– Easy-to-use touch-panel GUI


ICP Etch Systems for Batch GaN Plasma Etching

 

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  • SAMCO Etch System for GaN

 Featured Solutions

 SAMCO has developed AlGaN/GaN etch processes for GaN power device fabrication.

 Please visit our featured solution page for more detail.

Any Questions?

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