Manufacturing a heterobipolar transistor and a laser diode on the same substrate

摘要

A heterobipolar transistor HBT and a laser diode LD are manufactured from a common epitaxial structure having a plurality of semiconducting layers. The transistor can be manufactured directly from the material as it is after finishing the epitaxial steps. For manufacturing the laser diode the structure is changed by diffusing zinc into the material, so that the topmost material layers change their dopant type from n-type to p-type. This is made on selected areas of a wafer, so that transistors and laser diodes thereby can be monolithically integrated. The active region of the laser is located in the collector of the transistor, which gives a freedom in designing the components and results in that an individual optimization of the two components can be made. The laser and the HBT can thus be given substantially the same structures, as if they had been individually optimized. The laser will for example be the type vertical injection and can therefor get the same performance as discrete lasers.