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) structures with InGaAs channels was investigated at room temperature in the frequency range from 0.4 Hz to 100 kHz. The experimental results on the gate-bias dependent 1/f noise in MBE-grown InAlAs/InGaAs/InP heterostructure field-effect transistors (HFET's) biased in the ohmic region were interpreted in 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 dependence of the Hooge parameter alpha(Hg) of the gated channel region on the bias dependent mobility mu(g). The assumed inverse proportionality between alpha(Hg) and mu(g) due to Coulomb interactions near pinchoff allows an exact description of the noise behavior in the whole bias range. Additionally, tbe 1/f noise in ungated 2DEG structures of three different MOCVD-grown Al-free and five different MBE-grown Al-containing InP-based heterostructures 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 dependence on mobility (alpha(H) similar to mu(-2.6)). The lowest observed Hooge parameter alpha(H) = 1.5 x 10(-5) corresponding to the sample with the highest mobility was attributed to two-dimensional (2-D) phonon scattering processes.