In InP microchannel epitaxy (MCE) by liquid-phase epitaxy (LPE), a Sn + In solution is used to grow a layer with n-type doping. The high solubility of P in Sn gives high interface supersaturation (sigma(i)), which results in a low MCE width to thickness ratio (W/T ratio). To decrease sigma(i) and to obtain a wide MCE layer, an InP upper source was employed. By changing the size of the upper source, the growth condition was optimized and wide dislocation-free n-type TnP MCE layers, whose widths were as large as 250 mu m, have been obtained on Si substrates. An InP-based MQW structure was grown on an MCE layer on an Si substrate by MOCVD. Photoluminescence measurements of the structure revealed that the optical quality was as excellent as that of the structures grown directly on InP substrates.