Long wavelength transmitter opto-electronic integrated circuit

Abstract

A long wavelength transmitter OEIC includes a transverse direction current injection type semiconductor laser and a high electron mobility transistor which are integrated on a semi-insulating substrate. The semiconductor laser includes at least an AlGaInAs lower cladding layer, a quantum well active layer and a high resistivity AlGaInAs upper cladding layer successively grown on the semi-insulating substrate, disordered regions formed in the quantum well active layer by diffusions of p type and n type dopants, and an active region sandwiched by the disordered regions. The transistor includes an operating layer and a carrier supplying layer both including AlGaInAs series material and formed on the high resistivity AlGaInAs upper cladding layer. This transistor uses the upper cladding layer as a leakage current preventing layer. This structure can be formed by only one epitaxial growth, resulting in low cost. In addition, since the above layers are successively grown on a flat substrate, photolithography processes for forming a gate of HEMT are performed on a flat surface, so that a fine gate pattern can be formed with high precision. As a result, a transmitter OEIC performing high speed modulation are produced.