A distribution coefficient, K, can be used to simply and effectively track how species distribute between the gas phase and solid phase. Alfalight, Inc., a manufacturer of high-power laser diodes, uses this coefficient in several aspects of epitaxial growth for laser diode production. First, Alfalight, Inc. uses K over different materials and across a wide range of material compositions within a specific material system to study the incorporation dependencies of species as a function of growth conditions. K as a function of material composition will be discussed with special attention paid to the InxGayAl1-x-yP materials system. InxGayAl1-x-yP is particularly interesting because the A1 incorporation factor increases with increasing A1 composition in the epitaxial layer. In addition, the K factor methodology lends itself to the use of statistical process control (SPC) methods. Alfalight, Inc. has used SPC to prove that the MOVPE process can be considered to be an in-control process-a significant benefit to manufacturability. The use of the K factor methodology as an SPC tool will be discussed with specific examples. The major advantage of the K-factor methodology is that it allows control of the growth of the wide composition range of III-V semiconductor layers that Alfalight, Inc. uses to manufacture multi-mode broad area lasers (MMBAL) and single mode lasers at 808, 915, and 980 nm emission wavelengths, for example. 2003 Elsevier B.V. All rights reserved.