The 1/f noise of InP based 2DEG devices and its dependence on mobility

The 1/f noise of various InP-based two-dimensional electron gas (2DEG) stru ctures with InGaAs channels was investigated at room temperature in the fre quency range from 0.4 Hz to 100 kHz. The experimental results on the gate-b ias dependent 1/f noise in MBE-grown InAlAs/InGaAs/InP heterostructure fiel d-effect transistors (HFET's) biased in the ohmic region were interpreted i n the framework of a model which considers a separation of the HFET into a parasitic and the gated channel region. The results reveal a significant de pendence of the Hooge parameter alpha(Hg) of the gated channel region on th e bias dependent mobility mu(g). The assumed inverse proportionality betwee n alpha(Hg) and mu(g) due to Coulomb interactions near pinchoff allows an e xact description of the noise behavior in the whole bias range. Additionall y, tbe 1/f noise in ungated 2DEG structures of three different MOCVD-grown Al-free and five different MBE-grown Al-containing InP-based heterostructur es with InGaAs channels was investigated with respect to the channel design . In spite of various channel designs with mobilities between 6470 cm(2)/Vs and 11 500 cm(2)/Vs, the Hooge parameter of all devices showed a clear dep endence on mobility (alpha(H) similar to mu(-2.6)). The lowest observed Hoo ge parameter alpha(H) = 1.5 x 10(-5) corresponding to the sample with the h ighest mobility was attributed to two-dimensional (2-D) phonon scattering p rocesses.