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 α_Hg of the gated channel region on the bias dependent mobility μ_g. The assumed inverse proportionality between α_Hg and μ_g due to Coulomb interactions near pinchoff allows an exact description of the noise behavior in the whole bias range. Additionally, the 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 cm²/Vs and 11 500 cm²/Vs, the Hooge parameter of all devices showed a clear dependence on mobility (α_H~μ^-2.6). The lowest observed Hooge parameter α_H=1.5×10^-5 corresponding to the sample with the highest mobility was attributed to two-dimensional (2-D) phonon scattering processes