Using Auger electron spectroscopy (AES) and secondary ion mass spectrometry (SIMS) we examined the InP encapsulation properties of chemically vapor-deposited SiO2, chemically vapor-deposited phosphosilicate glass (PSG) and r.f.-plasma-deposited Si3N4. Following 60 min 750°C anneals, indium is detected by both AES and SIMS on the surfaces of Si3N4 encapsulants. SIMS results also suggest that indium may out-diffuse through PSG caps during similar anneals. Silicon in-diffusion from the cap to the underlying InP is found to be significant in annealed SiO2-and Si3N4-capped samples. Little such silicon contamination of InP is observed after annealing with PSG encapsulation.

We observed cracking in chemically vapor-deposited SiO 2 encapsulating layers on InP when these samples were annealed at temperatures above 650°C. Using optical microscopy, scanning electron microscopy and Auger electron spectroscopy we studied the detailed nature of this form of film failure. Thermally induced stress between the film and the InP does not fully account for the phenomena reported here. The observed cracking apparently results from an interaction between mechanical stress, chemical effects and possibly defects in the SiO 2 layers.

Data are presented showing that two different mechanisms control the LPE growth of InGaPAs in the step-cooled technique. An automated growth apparatus, which allows an accurate and reproducible selection of growth times as short as ~9ms, is used to study the thickness and the growth rate of InGaPAs layers as a function of growth time for times ranging from ~9ms to ~20s. For long intervals the measured InGaPAs epilayer thickness is shown to vary as the square root of the growth time, as expected for the case of diffusion-limited growth. When the growth period is reduced to < 200ms , the quaternary layer thickness is greater than the diffusion-controlled value and, in addition, is practically independent of the growth time. Auger depth profile data on InGaPAs layers grown from ~ 9ms to ~ 120ms are presented showing that layers are uniform in composition. Photoluminescence data on InGaPAs layers grown under non-diffusion limited conditions are shown to be different in composition than the relatively thick layers grown under diffusion-limited conditions, at longer times, from melts with the same liquidus compositions. Data are presented indicating the existence of both of these distinct compositions in a single ~ 800 Å InGaPAs layer grown in ~ls. It is shown that thick InGaPAs layers of uniform composition can be grown, by the step-cooled LPE process, by stacking a number of thin layers grown in short intervals. Data are presented indicating that thin-layer stacks can be used to improve the performance characteristics of heterostructure lasers.