LARGE-SCALE MOVPE PRODUCTION SYSTEMS

High-performance ICs and OEICs rely on complex epitaxial heterostructures with tight bandgap engineering. Related development and production require homogeneous material, manufacturing of batches of comparable wafers, in-situ multiwafer fabrication, reduced surface contamination and defect density along with proven heterostructure processes for many combinations of III-V materials. The application of substrate rotation always seemed to cause technical problems, such as particle generation, mechanical feed troughs etc., rather than to improve the process from a production point of view. This paper summarizes the breakthrough in III-V multiwafer MOVPE mass production applications using the planetary multiwafer reactor with gas foil rotation (5 x 3"/7 x 2" or 5 x 4"/8 x 3") which was originally developed and patented by Philips LEP for growth of GaAs/AlGaAs heterostructures and has been used successfully since then for HEMT production, laser fabrication, and GaInP deposition. In similar Planetary Reactors, GaAs- and InP-based materials for a wide range of optoelectronic applications have been produced. The use of low pressures is not only advantageous for the handling of phosphorus-containing compounds and reduction of overall gas consumption, but also allows to drastically reduce the amount of H-2 required for driving the wafer support. The variation of thickness in these multiwafer systems is reduced to the order of 1-2% for GaAs, AlGaAs, GaInP, InP, GaInAs and GaInAsP (1.55, 1.3, 1.05-mu-m). Thus, one major advantage in comparison to MBE is that these reactors are capable of handling both GaAs- and InP-based processes with high concentration of phosphorus. Processes for the production of visible lasers (AlGaInP), GaInP HBTs, or complex solar cell structures have also been developed. This finally makes this MOVPE technology by far superior over MBE for production application. The relatively simple realization of a variety of different wafer sizes emphasizes the efforts to create even larger reaction chambers capable for large-area epitaxial growth of different material systems. The use of silicon wafers as substrates for advanced device structures is no longer limited to 2" or 3" wafers, also 4", 6", and 8" wafers can be used, and rectangular arrangements for solar cell production are being developed.