Double δ-doped enhancement-mode InGaP/AlGaAs/InGaAs pseudomorphic high electron mobility transistor for linearity application

A high linearity and high efficiency enhancement-mode InGaP/AlGaAs/InGaAs pseudomorphic high electron mobility transistor (PHEMT) for single supply operation has been developed. The low voltage operation is achieved by the very low knee voltage of the device and the linearity is improved by the optimizing concentrations of the two 3 delta-doped layers. Biased at drain-to-source voltage V-DS = 2V, the fabricated 0.5 x 200 mu m(2) device exhibited a maximum transconductance of 448 mS/mm. The measured minimum noise figure (NFmin) was 0.86 dB with 12.21 dB associated gain at 10 GHz. The device shows a high output third-order intercept point (OIP3)-P-1dB of 13.2 dB and a high power efficiency of 35% when under wideband code-division multiple-access (W-CDMA) modulation signal.