Photonics – Ion Beam Solutions

Several fabrication processes in photonics are discussed below. Please contact us for more technical discussions about your specific application!

Ion Beam Sputtering – Si3N4 Waveguides:

Dual Ion Beam sputtering (DIBS) is the recommended process for depositing very precise and dense thin films. For Si3N4 deposition, an argon ion beam extracted from the primary source physically sputters a Si target. This sputtered material is combined with nitrogen gas (in the chamber or assist source) to reactively condense on the substrate as silicon nitride. Furthermore, final film stoichiometry is precisely controlled through various process parameters. The assist source also serves as a pre-clean etch and as an additional energy source for further film densification during deposition.

  • Excellent uniformity <1%
  • High refractive index: 2.00 – 2.15
  • Extremely precise in-situ optical properties and thickness monitoring and control

Ion Beam Trimming – Uniformity Improvement:

Ion beam trimming is a scanning, focused argon ion beam etch for final uniformity correction.

There are uniformity limitations to all deposition methods. Some applications require extreme uniformity that are unobtainable from these deposition tools, or even other auxiliary processes such as CMP. Moreover, in high volume manufacturing applications, the uniformity of certain key thin film could make a tremendous yield impact.

The example to the right shows 21x factor of improvement of a silicon nitride thin film layer down to 0.14nm RMS standard deviation.

  • No change in roughness or RI
  • Angstrom precision possible
  • Can physically etch all materials
  • Spot size adjustable down to 1mm
  • Thickness trimming of
    waveguides and other thin films

Ion Beam Milling or Etching – LN Waveguides:

LiNbO3 (LN) waveguides require near-vertical and smooth sidewalls to achieve desired optoelectronic properties. The capabilities of ion beam etching (IBE) enables such device fabrication specifications to be met, more so than other etching methods such as reactive ion etching (RIE).

Since IBE is a physical etching method, it is capable of etching all materials. F and Cl -based reactive gases can be supplemented to tune etch selectivities.

  • Directionality of etch
    • Vertical, smooth sidewalls
    • Slanted, smooth sidewalls
  • Excellent uniformity <1%
  • In-situ sidewall redeposition/fencing removal
  • SIMS or OES end point detection and etch material monitoring
  • Tiltable and rotatable substrate
  • He backside contact cooling with water
    • Chiller available for even lower temperatures
  • F and Cl reactive etching possible