Low-frequency noise characteristics of highly-strained In0.5Ga0.5P/In0.33Ga0.67As pseudomorphic high electron mobility transistor

Highly strained In0.5Ga0.5P/In0.33Ga0.67As and conventional In0.5Ga0.5P/In0 .22Ga0.78As pseudomorphic high electron mobility transistor (p-HEMT) struct ures were grown on patterned and non-patterned GaAs substrates, respectivel y, by using a compound-source molecular beam epitaxy. Microwave characteris tics and low-frequency noise characteristics of the p-HEMTs were measured a nd compared. The highly strained InGaP/In0.33Ga0.67As p-HEMT grown on the p atterned substrate showed more than 20% improvements in microwave performan ces including the transition frequency (f(T)) and the maximum oscillation f requency (f(max)) compared with those of the conventional InGaP/In0.22Ga0.7 8As p-HEMT grown on the non-patterned substrate. The input noise spectral d ensity and the Hooge parameter of the highly strained InGaP/In0.33Ga0.67As p-HEMT grown on the patterned substrate were more than an order of magnitud e lower than those of the conventional InGaP/In0.22Ga0.78As p-HEMT grown on the non-patterned substrate. The improvements in microwave characteristics and low-frequency noise characteristics of the highly strained InGaP/In0.3 3Ga0.67As p-HEMT are attributed to the improvement in transport property of the highly strained In0.33Ga0.67As channel layer achieved by a patterned s ubstrate growth. The results indicate the potential of highly strained p-HE MTs grown on patterned substrates for use in applications requiring improve d microwave and low phase noise characteristics. (C) 2001 Elsevier Science Ltd. All rights reserved.