We studied the properties of the InAs epitaxial layers grown of (100)-oriented GaAs (tilted toward) by molecular beam epitaxy. From DCX (double-crystal x0ray), the better crystal quality was shown in InAs epitaxial layers on about 2500 GaAs epitaxial layers on GaAs, we obtained the high mobility of InAs epitaxy in As/In BEP ratio (1.2~2.0) from Hall effect measurement. The electron mobility ... [Show full abstract] increased as electron concentration increases, until Si cell temperature . The mobility decreases as the Si cell temperature increases, at the temperature over . We obtained the high mobility (1.10104cm2/V.s) at Si electron concentration of .