Abstract
In this study, we used the sealed-quartz-ampoules to produce ZnAs2 as our diffusion source to perform Zn diffusion, and optimized the deposition process by varying parameters to deposit silicon nitride films and adjust the refractive indices to be in the range of 2.0 to 2.05, utilizing its characteristics of having a denser and less permeable structure than SiO2 to inhibit the Zn diffusion and IILD. We used sealed quartz ampoules to do all diffusion experiments. At first, we did the Zn diffusion into n+GaAs (Si doped~1018cm-3) substrates with ZnAs2 as the diffusion source at different diffusion temperatures for various times. Among three temperatures, we chose 600℃ to perform our Zn diffusion studies for different Al contents of AlxGa1-xAl (~2um) layer on GaAs substrate and Al1-xGaxAs / GaAs structures. We have demonstrated layer disordering in two Al1-xGaxAs/GaAs structures, Sample A and B. The disordering was induced by Zn diffusion with ZnAs2 as the diffusion source. The PL data show that we can effectively control the extent of disordering by varying the diffusion time at 600℃. Moreover, we can use a SiNx as diffusion mask to effectively inhibit Zn diffusion to preserve the crystal "quality" and keep the active layer during Zn diffusion as sharp as the as-grown one.