Modeling of Zn Diffusion in InP/InGaAs Materials During MOVPE Growth

Zn, a p-type dopant in III-IV material, has been commonly used, especially for InP based laser diodes. However Zn is a very fast diffuser and it is very difficult to precisely control the grown-in Zn profile after epi growth. Since the final Zn diffusion front is critical to laser performance, a precise control of hte Zn profile in the laser structure is important. As a result, understanding Zn diffusion in the InP/InGaAs materials system during epi growth is very important. The goals of this study are to understand Zn diffusion behavior in InP/InGaAs material and to establish a Zn diffusion model that can be used as a laser fabrication process modeling tool. To investigate the change of the Zn profile after each epi growth process, and extract the Zn diffusivity in both InP and InGaAs materials, we chose simple InP/InGaAs heterostructures with different Zn doping conditions grown by MOVPE. Figure 1 shows the structure of the as-grown sample. Samples were submitted for SIMS measurements after each epitaxial growth. Table 1 lists the different Zn doping levels in the as-grown sample submitted to SIMS measurement.