ATMOSPHERIC AND LOW-PRESSURE SHADOW MASKED MOVPE GROWTH OF INGAAS(P) INP AND (IN)GAAS/(AL)GAAS HETEROSTRUCTURES AND QUANTUM-WELLS/

The shadow masked growth technique is presented as a tool to achieve t hickness and bandgap variations laterally over the substrate during me talorganic vapor phase epitaxy. Lateral thickness and bandgap variatio ns are very important for the fabrication of photonic integrated circu its, where several passive and active optical components need to be in tegrated on the same substrate. Several aspects of the shadow masked g rowth are characterized for InP based materials as well as for GaAs ba sed materials. Thickness reductions are studied as a function of the m ask dimensions, the reactor pressure, the orientation of the masked ch annels and the undercutting of the mask. The thickness reduction is st rongly influenced by the mask dimensions and the reactor pressure, whi le the influence of the orientation of the channels and the amount of undercutting is only significant for narrow mask windows. During shado w masked growth, there are not only thickness variations but also comp ositional variations. Therefore, we studied the changes in In/Ga and A s/P ratios for InGaAs and InGaAsP layers. It appears that mainly the I n/Ga-ratio is responsible for compositional changes and that the As/P- ratio remains unchanged during shadow masked growth.