Patent ID: 7588954

Claim:
Method for making an InGaAs/GaAs quantum well laser ( 10 ) on a Silicon substrate ( 15 . 1 ), the method comprising the following steps: formation of a virtual Germanium substrate ( 15 ) on the Silicon substrate ( 15 . 1 ) by means of a low-energy plasma-enhanced chemical vapour deposition (LEPECVD) process, whereby said virtual Germanium substrate ( 15 ) comprises a pure Germanium layer ( 15 . 3 ; 15 . 4 ), said Germanium layer ( 15 . 3 ; 15 . 4 ) having a thickness between 0.5 μm and 2 μm, formation of a Gallium Arsenide structure on the virtual Germanium substrate ( 15 ) by means of a metal organic chemical vapour deposition process, said metal organic chemical vapour deposition process comprising an initial step for the formation of a first Gallium Arsenide layer ( 16 ; 21 ) on said virtual Germanium substrate ( 15 ) at a first substrate temperature (T s1 ), a second step for the formation of a second Gallium Arsenide waveguide layer ( 17 ) at a second substrate temperature (T s2 ), said second substrate temperature (T s2 ) being higher than said first substrate temperature (T s1 ) and said first Gallium Arsenide layer ( 16 ; 21 ) being thinner than said second Gallium Arsenide layer ( 17 ), and subsequent steps for the formation of an active laser structure comprising a Gallium Arsenide waveguide layer ( 12 ) embedding a quantum well ( 11 ).