| 摘要 |
PURPOSE:To make it possible to form the cathode electrode of a laser on the surface of an element, and make high-speed operation of the element possible, by forming a first clad layer and an active layer on a semi-insulating substrate, forming a second clad layer and a collector layer on the active layer, and burying insulator between the second clad layer and the collector layer. CONSTITUTION:On a semi-insulating substrate 1, a first clad layer 2 of one conductivity type and an active layer 3 are formed, and on the active layer 3, a second clad layer 4 of inverse conductivity type and a collector layer 7 of one conductivity type are formed. The second clad layer 4 is in the form of a stripe and injects a current into the active layer 3. Insulator 15 is buried between the second clad layer 4 and the collector layer 7. For example, on a semi-insulating InP substrate 1, the following are formed: an N-type InP first clad layer 2, an InGaAsP active layer 3, a P-type InP second clad layer 4, and a P-type InGaAsP cap layer 5. After selective etching, the following are formed: an N-type collector layer 7, a P-type InGaAsP base layer 8, an N-type InP emitter layer 9, and an N-type InGaAsP emitter contact layer 10. Then, polyimide buried regions 13 and 15 are formed.
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