Enhancement-mode (E-mode) operation In0.49Ga0.51P/In0.2Ga0.8As/GaAs PHEMTs were designed for high performance and were successfully grown by gas source molecular beam epitaxy (GSMBE). An optimind GSMBE growth process based on the memory effect studied has been applied to precisely control the,InGaP/InGaAs and InGaP/GaAs interface quality and composition. The lattice mismatch of 10(-4) and composition uniformity of better than +/-0.2% for 3" diameter InGaP/GaAs layers were obtained. E-mode operation InGaP/InGaAs PHEMTs and related low-noise amplifier (LNA) circuits were obtained. The E-mode PHEMT had a threshold voltage near 0 V and the LNA can. operate under a single-voltage supply of 1.5-3.0 V and at 2.5 GHz with a gain of over 20 dB and a noise figure (N-f) of 3.43 dB. (C) 2003 Elsevier Science B.V. All rights reserved.