| 摘要 |
The present invention is a method for making multi-quantum well structures having superior interfacial crystalline quality. In particular, it is an LP-MOCVD crystal growth method using continuous growth stages to produce well-defined heterojunctions of uniform thickness for multi-quantum well (MQW) lasers, including MQW lasers structures having output wavelengths less than approximately 1.55 mu m. The continuous growth stages are characterized by essentially instantaneous gas switching sequences from a first gaseous mixture used to grow separate confinement layers (SCL) and barrier layers to a second gaseous mixture used to grow quantum well layers. By continuous growth stages it is meant that there is no intentional pause between well and barrier layer growth stages, that is, the gaseous mixture used for a particular growth stage is introduced into the LP-MOCVD reactor just as the last of the previous gaseous mixture is venting out of the reactor. Surprisingly, it appears that the continuous growth stages of the present invention decrease the pressure transients that exist during gas switching sequences in conventional LP-MOCVD methods, thereby minimizing if not eliminating all lateral thickness modulation in the well and barrier layers by suppressing the tendency for the growth to proceed in a three dimensional manner.
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