Learn how SENTECH plasma systems and metrology tools are ideal for processing advanced optoelectronics applications.


Optoelectronics is a fast-emerging technology field that consists of applying electronic devices to sourcing, detecting, and optical properties and control of light. Applications include VCSELs, micro-LEDs, and microlenses, all of which have a growing demand in a large number of industrial end-users, including aerospace, space, automotive, consumer electronics, information technology, and healthcare.


The SENTECH plasma product family provides highly effective solutions for many leading-edge optoelectronic-based applications.  The SENTECH SI 500 D ICPECVD system can be used for effective trench filling for Micro LED applications often used in flat panel devices.

The ICP-RIE plasma etch system with the PTSA source SI 500 offers a highly selective and low-damage etch with accurate endpoint detection of vertical and tapered GaAs-based VCSELs. The SENTECH SI 500 ICP-RIE System equipped with the Planar Triple Spiral Antenna (PTSA) 200 enables low-damage etching of GaN- and InP-based devices to structure waveguides and microlenses. Microlenses offer extremely efficient light extraction in LED fabrication or can be used for focussing light. Smooth, vertical, low-loss waveguides and facets for light coupling were also demonstrated in SiN and SiO.

Learn more about the successful ICP-RIE etch of InP Pillars with the SENTECH SI 500 ICP-RIE etch system

Two-dimensional photonic crystals (PhCs) offer a huge potential in photonic integrated circuits. They can be used to miniaturise existing integrated optical devices, e.g., bends, microcavities, add-drop filters, and band-edge lasers. InP pillars were successfully etched as a test pattern, verifying the suitability of the etching by the SENTECH SI 500 ICP-RIE System equipped with a proprietary SENTECH PTSA ICP Plasma Source. The sidewalls of the InP pillars were

vertical with very little roughness and a smooth bottom surface was achieved and a very high selectivity to Ni/SiO2 mask was observed during InP etching.

Dynamic temperature control of the electrode maintaining a constant sample temperature during the complete etch process and stable plasma at low pressures are the key features for the successful etching of InP pillars. The SENTECH SI 500 ICP-RIE system is equipped with the Planar Triple Spiral Antenna (PTSA), an inductively coupled plasma (ICP) source with narrow ion energy distribution and very low ion energies. The SENTECH proprietary PTSA is a unique planar plasma source that enables low-damage etching.

Discover more about the successful etching of Lithium Niobate (LiNbO3) ridge waveguides

Lithium Niobate (LiNbO3, or LN) is a non-linear crystal material exhibiting properties such as large electro-optic coefficients, piezoelectric properties, large transparency range, and wide intrinsic bandwidth. Furthermore, LiNbO3 on insulator (LNOI) will allow the fabrication of high contrast optical waveguides, and high integration density photonic integrated circuits (PICs) and thus, finally, open a new generation of miniature rf modulators.

The etching of smooth ridge waveguides is the most crucial step to fabricate PICs. As LiNbO3 is a relatively hard crystal material dry etching often results in high surface roughness and re-deposition on sidewalls which lead to optical losses and poor device characteristics. Sulfur Hexafluoride (SF6) gas or SF6/Argon (Ar) mixing gas is widely used in plasma processes to etch LiNbO3, however, a high bias power is necessary for physically-assisted desorption of such non-volatile fluorides to avoid surface roughening via micro-masking.

To enhance the etch rate and improve selectivity to the SiO2 mask, the SENTECH SI 500-RIE System utilises the exclusive SENTECH Planar Triple Spiral Antenna (PTSA) and an inductively coupled plasma (ICP) source for high plasma density. This system also provides excellent dynamic temperature control. THE SENTECH Laser Interferometer (SLI 670) was used to provide a fully software-integrated process observation.

Using a specifically designed etch process with a suitable gas chemistry combined with bias power we successfully etched LiNbO3 ridge waveguides with smooth sidewalls at a good level of verticality using the SI 500 in ICP-RIE mode. The profile was not compromised and a good selectivity without any re-deposition on the sidewalls was achieved. The SENTECH SLI 670 accurately recorded and stopped the etching process at precisely the desired thickness.

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Systems and related products

Cluster Configuration for Plasma Etching and Deposition

SENTECH Cluster Tools comprise plasma etching and / or deposition modules, transfer chamber and vacuum load lock or cassette station for flexibiliy in wafer handling.

ICP-RIE Plasma Etch System – SI 500

The SENTECH SI 500 ICP-RIE high-end plasma etch system uses an inductively coupled plasma (ICP) source with low ion energy for low-damage etch and nanostructuring.

ICPECVD System – SI 500 D

Inductively coupled plasma (ICP) deposition system, the SENTECH SI 500 D for high density, low ion energy, and low-pressure plasma deposition of dielectric films and low-damage, low-temperature deposition for passivation layers.