Patent ID: 8252670

Claim:
A production method for a lateral electro-optical modulator on an SOI substrate, the modulator comprising a rib waveguide formed in a thin layer of silicon of the SOI substrate, the rib waveguide being placed between a doped region P and a doped region N formed in the thin layer of silicon, the rib waveguide occupying an intrinsic region of the thin layer, the doped region P, the intrinsic region, and the doped region N constituting a PIN diode structure, at least one doped zone P being formed in a rib of the waveguide and perpendicular to the substrate, the method comprising: masking steps of the thin layer of silicon using a hard mask having a pattern that defines therein the rib of the waveguide, said pattern of the hard mask having an internal slot which defines said at least one zone to be doped P in the rib of the waveguide, and external edges which define a limit of a zone to be doped N relative to the rib of the waveguide; producing the rib by etching the thin layer of silicon, said rib being defined by the pattern of the hard mask; masking the thin layer of silicon to delimit a region to be doped P; doping the region to be doped P, said region to be doped P being defined by the internal slot of the hard mask; masking the thin layer of silicon to delimit a region to be doped N; and doping the region to be doped N, a limit of the region to be doped N being defined the external edges of the hard mask.