Method of making ridge waveguide lasers

A method of producing an optical ridge waveguide semiconductor device having a base semiconductor portion and first and second spaced apart elevated semiconductor portions thereon, said method comprising the steps of:

• (a) producing an initial semiconductor structure by the steps of (i) depositing dielectric and then resist onto a planar semiconductor surface, (ii) opening a window in the resist over a region corresponding to the uppermost surface of the first elevated portion to be formed, (iii) employing a suitable reagent to undercut the resist down to the level of the semiconductor surface, (iv) depositing metal onto the semiconductor surface thus exposed in the image of the window of the resist, and (v) removing the resist and any metal deposited thereon to thereby form the uppermost portion of the first elevated portion carrying a layer of metal thereon and the uppermost portion of the second elevated portion carrying a layer of dielectric thereon, said uppermost portions of the first and second elevated portions being disposed over first and second semiconductor material regions of said initial semiconductor structure;
• and
• (b) producing the optical ridge waveguide semiconductor device from the initial semiconductor structure by applying an etchant to the initial semiconductor structure so as to remove semiconductor material between said first and second semiconductor material regions without removing the respective layers on the uppermost portions of said first and second elevated portions.