Buried heterostructure lasers using MOCVD growth over patterned substrates

A buried heterostructure laser, which comprises:

• a compound semiconductor structure and a top and a bottom electrode to the said structure, said structure comprising in an ascending order
• a substrate of one conductivity type, a buffer layer of said one conductivity type, a bottom confining layer of said one conductivity type, an active layer, a top confining layer of another conductivity type, and a contact layer of said another conductivity type, in which
• said substrate has two parallel grooves forming a reentrant mesa and shoulder sections, each of said grooves having a dovetailed cross-section, said buffer layer, said bottom confining layer and said active layer each having sections arranged in columns on the mesa, in the grooves and on the shoulders, each of said sections in one column being laterally discontinuous with respect to the related sections in adjacent columns, said top confining layer overlaying sections of the active layer on top of each column and sloped walls of sections of the buffer layer, bottom confining layer and active layer so as to bury the section of the active layer of the column above the mesa and separate this section from other columns,
• a dielectric layer on the contact layer, said dielectric layer having a window coxetensive with the mesa,
• a top electrode in contact with the contact layer exposed in said window, said top electrode being also coextensive of the mesa, and
• an overlay electrode on the whole of the upper surface of the said top electrode and of said dielectric layer and forming contact to the top electrode.