THE EFFECT OF INP BUFFER LAYER ON THE ELECTRON-TRANSPORT PROPERTIES OF EPITAXIAL IN1-XGAXAS

Carrier concentration and mobility of undoped InGaAs layers grown on InP via organometallic vapor phase epitaxy have been investigated. The mobility limits imposed by various scattering mechanisms were studied over the temperature range 40 to 300 K. Electrons in InGaAs epilayers grown on semi-insulating InP substrates without any InP buffer layer had a lower 77 K mobility than others grown with an undoped InP buffer layer. This is attributed to a higher acceptor compensation in the unbuffered layers (as determined from temperature dependent carrier concentration data) and to significant ionized-impurity scattering in these more compensated samples.