Chip Technology

The FBH runs wafer processing lines for ridge waveguide lasers (RW), broad area laser diodes (BA) and tapered laser (TL) diodes, designed for use as single emitters or bars. Monolithic-frequency-stabilization of diode lasers (DBR- and DFB-lasers) is also enabled by using internal grating structures, produced by surface etching or 2-step epitaxial techniques.

Processed 3-inch wafer
Processed 3-inch wafer

Processes

TEM of an epitaxially overgrown grating
TEM picture of an epitaxially overgrown grating realized by holographic lithography
SEM of an etched surface grating before removal of the residual resist mask
SEM picture of an etched surface grating before removal of the residual resist mask
  • Contact and projection lithography including periodical structures starting at 500 nm
  • Ebeam lithography for grating structures and ridges with critical dimension (CD) of 70 nm
  • Holographic illumination for small grating periods (160 .. 400 nm)
  • Ion implantation for current confinement
  • Wet chemical etching or reactive ion etching for lateral wave guiding
  • Ion beam sputtering or PECVD for isolators
  • Evaporation and sputter processes for p- and n-side contact metals
  • Electroplating of gold
  • Back end process (thinning, scribing and breaking)
  • Passivation of semiconductor surfaces via MBE for a stability of the facets up to 25 MW/cm2
  • Facet processing via ion beam sputtering for low to high reflections (≤ 10-4 .. > 98%)