Performance enhancement of p-GaAs_(0.51)Sb_(0.49)/ln_(0.53)Ga_(0.47)As hetero-junction vertical tunneling field-effect transistors with abrupt source impurity profile

摘要

The effects of source impurity concentrations and profiles on the electrical characteristics of Be- and C-doped p(+)-GaAs0.51Sb0.49/In0.53Ga0.47As vertical tunneling field-effect transistors (TFETs) are experimentally studied. The ON current (ION) and subthreshold swing (SS) of the GaAsSb/InGaAs TFETs, measured at 50 K to suppress the generation-recombination leakage current, are found to be improved by using C instead of Be as the source impurity. A minimum SS of similar to 20 mV/dec at V-D = 50 mV and an I-ON of 1.7 x 10(-6) A/mu m at V-D = 500 mV and V-G = 1.5 V are obtained at 50 K for C-doped p(+)-GaAsSb/InGaAs TFETs with the source acceptor concentrations of 4 x 10(19) and 7 x 10(19) cm(-3). The temperature dependence of the I-D-V-G characteristics suggests almost no difference in the crystal quality of the GaAsSb/InGaAs heterointer-faces between the source impurity species of Be and C. On the other hand, the results of secondary ion mass spectroscopy analyses show that the C profiles near the source-channel interfaces are steeper than the Be ones. Thus, the improved I-ON and SS of TFETs with the C-doped source region are mainly attributed to the improved abruptness of the p-type dopant profiles near the source-channel interfaces. Published under license by AIP Publishing.