| 摘要 |
PURPOSE:To obtain not only oscillation at a fundamental transverse mode but also oscillation at a low threshold by positioning an N type InP layer in a multilayer structure crystal constituting a buried layer consisting of InP or InGaAsP having the functions of the constriction of currents and the formation of an optical waveguide at a section lower than the end section of an active layer in mesa structure and the P- N junction section of InP. CONSTITUTION:An SiO2 film is formed onto the whole surface of a clad layer 4, and a mask 10 composed of SiO2 is shaped to a striped form. A hetero-growth section under the SiO2 mask 10 is left to an inverted mesa shape to form mesa structure. An active layer 3 is side-etched selectively. Second buried growth is conducted, and an N type semiconductor layer 5 and a P type semiconductor layer 6 are grown in succession. A P type InP buffer layer 2a and an N type InP clad layer 4 generates a mast lance port through heat treatment at that time at a position isolated by a groove 11 removed through the side etching of the active layer 3, and upper and lower InP layers are connected rapidly through a P-N junction surface 12. Regarding second buried growth, a buried layer is grown to a mesa-etched section by utilizing properties of which a crystal does not grow on SiO2 in liquid-phase epitaxial growth. The N type InP layer in 5 is controlled so as to be positioned on the side lower than 12 at that time, and the P type InP layer in 6 is grown. |
