Characterization of low-frequency noise behavior of MBE-grown InGaP/InGaAsp-HEMTs

The low-frequency noise characteristics of InGaP/InGaAs pseudomorphic HEMTs (p-HEMTs) grown by using compound source MBE are investigated for the freq uency range of I Wt to 52 kHz and the temperature range of 170 K and 370 K. Equivalent input noise spectra (S-iv) were measured as functions of the fr equency and the temperature. S-iv was measured to be 3.4 x 10(-12) [V-2/Hz] at 1 kHz for a 1.3 x 50 mum(2) InGaP/InGaAs pHEMT at room temperature. Mea surements of the low-frequency noise spectra and the transconductance (g(m) ) frequency dispersion of the p-HEMT as a function of temperature show that a trap with an activation energy level around 0.581 eV is the dominant tra p that accounts for the low-frequency noise behavior of the device. Deep le ver transient spectroscopy (DLTS) measurements of the Si-doped InGaP reveal three different traps with activation energy levels of 0.26 eV, 0.581 eV, and 0.622 eV. The deep level with an activation energy of 0.581 eV has the highest concentration. DLTS, low-frequency noise spectra, and g(m) frequenc y dispersion measurements consistently indicate that the low-frequency beha vior of the InGaP/InGaAs p-HEMT grown by using compound source MBE originat es from a deep trap in the InGaP barrier layer having an activation energy level around 0.581 eV. The-normalized extrinsic g(m) frequency dispersion o f the pHEMT was as low as 2.5 % at room temperature, indicating that the In GaP/InGaAs pHEMT grown by using compound source MBE had well-behaved low-fr equency noise characteristics.