Monolithic integration of InGaAsP/InP lasers and heterostructure bipolar transistors by selective area epitaxy

The authors describe the use of selective area epitaxy to prepare monolithically integrated lasers and heterostructure bipolar transistors based on InGaAsP/InP. Selective growth offers a versatile method of lateral integration of structurally dissimilar devices with the different device structures grown side by side in different growth cycles. Individual devices can be optimised separately without any performance compromise. Bipolar transistors grown on the semi-insulating current blocking layers of the buried heterostructure lasers show high gain, high breakdown voltage and excellent high current stability. Laser threshold is reached at a base current as low as 160 mu A and the light output is linear with current to 10 mW.