Highly resistive FET buffer layers on InP grown by LP-MOVPE

Electrical characteristics of field effect transistors (FETs) grown on Fe-doped InP substrates are extremely dependent on the presence of a buffer with suitable resistivity below the active channel. The growth of a semi-insulating (SI) buffer layer on the InP substrate is required to compensate the n-type impurities (silicon) accumulation on the epi-ready substrate surface, responsible for parallel conduction at the substrate/buffer interface. Known techniques to prevent parasitic conduction in MOVPE growth could not be reproduced successfully in our reactor or were not compatible with the use of patterned substrates for OEIC processing. In this report, we describe new growth methods of semi-insulating buffers, using low pressure metalorganic vapor phase epitaxy. In both cases, specific growth procedures described below have allowed complete compensation of the electrical activity of n-type impurities at the interface