Improved composition and thickness control of III-V epitaxy in a metalorganic chemical vapor deposition process

Metalorganic chemical vapor deposition (MOCVD) is a promising technology for the fabrication of high speed electronic and opto-electronic devices. Commercial application of this technique is limited by a high degree of process variance. This paper describes work in progress on the development of a closed loop MOCVD facility for GaAs device fabrication. Critical system disturbances, which degrade the growth rate uniformity and reproducibility, and subsequent device performance, are identified. A control system is designed and implemented to regulate the supply of gallium to the reactor. The controller performance is investigated by growing GaInAs/InP superlattices. Post-growth tests clearly illustrate that the compensated samples have better precision in alloy composition and thickness.