InGaAs

InGaAs is used to form the channel material in certain advanced NMOS transistor structures, exploiting its higher electron mobility than silicon's to improve transistor switching speed for a given gate length. Integrating III-V channel material like InGaAs with an otherwise silicon-based process flow is a genuinely difficult heterogeneous integration challenge, since III-V and silicon crystal structures and lattice constants differ, requiring specialized epitaxial growth and interface engineering to combine the two materials without introducing excessive defects at their junction.