Multiwafer gas source molecular beam epitaxial system for production technology

Abstract

High throughput epitaxial wafer production is demonstrated by using a newly designed multiwafer gas source molecular beam epitaxy apparatus. The actual application data show excellent results of uniformity, cost performance, and material performance through practical mass production operation. Electron mobility as high as 124 000 cm2/V s is obtained at 77 K for a 7-μm-thick GaAs layer with a carrier concentration of 7.7×1013 cm−3. A typical surface defect density of 25 cm−2 is achieved for continuously grown 1.7-μm-thick metal–semiconductor field effect transistor (MESFET) structures. The uniformity of sheet resistance in n-GaAs and AlAs mole fractions in AlGaAs is less than 2.0% (1.5% and 0.27%, respectively) over a 27 cm diameter area. A quantitative throughput number for a typical growth of a MESFET structure is four 4 in. or seven 3 in. diameter wafers per 2.5 h in a continuous process flow.