LETI Photodetector Technology


Germanium Photodetector MPW


For the first time, ePIXfab offers affordable access to a standardized MPW active silicon photonic IC technology with germanium detectors.


In order to ensure low-cost, quick access, scalability to manufacturing and overall maturity of silicon photonic IC technology, LETI will offer in July 2012 passives and  lateral p-i-n germanium photodetectors  which are grown at the end of silicon waveguides by selective epitaxial growth. Users can access this technology

either with their own design while following specific design rules, or

with ‘LETI photodetector design’ with parametric performances targeted but not guaranteed, see specs below.

  • Responsivity e.g. > 0.5A/W
  • Dark Current < 3uA @-0.5V bias
  • Bandwidth > 10GHz at -3dB in S21 @ -2V bias

Fabrication information:
Passive structures (2 mask layers DUV 193nm)


  • on SOI substrate with BOX: 2µm, Si: 220 nm
  • Grating couplers with shallow etching of 70nm
  • waveguide with 220 nm of full etching

Germanium PD’s fabrication (mask layers DUV 248nm)

  • Build Silicon recess down to 50 nm
  • Selective Ge growth by  RP-CVD in recess
  • Chemical Mechanical Polishing
  • SiO2 deposition
  • SiO2 openings define electrode spacing minimum 1µm
  • Implantation and thermal annealing
  • Ti / TiN / AlCu metal stack for fabrication of electrodes

Cost :
1 MPW block die: user design size 7 x 3.7mm
~ 15000 € (definitive  cost in June 2012)

Practical information:
GDS  file have to be sent before  7th August 2012 to Maryse Fournier.

For registration and to obtain the design kit, contact: Maryse Fournier, This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Last Updated (Wednesday, 30 May 2012 16:36)