Effect of low temperature RF plasma treatment on electrical properties of junctionless InGaAs MOSFETs

In this paper, we study the effect of low-temperature RF plasma treatment in forming gas (10%H2+90%N2) on the electrical characteristics of junctionless MOSFETs with n-In0.53Ga0.47As channel and an Al2O3 gate dielectric. The impact of plasma power density on the device parameters is investigated. It is found that RF plasma annealing with a low power density (0.5 W/cm2) at 150°C for 10 min provides substantial improvement of source/drain contacts resistance and the carrier mobility resulting in a considerable increase of the on-state current and transconductance. It also improves the subthreshold slope and reduces the fixed positive charge in Al2O3 under the gate, shifting the threshold voltage toward positive values. It is demonstrated that non-thermal factors play a principle role in modification of electrical properties of the JL MOSFETs under RF plasma treatment. Such treatment may be an efficient tool for the improvement of the performance of the advanced MOSFETs with III-V channel materials

Enhanced recrystallization and dopant activation of P+ ion-implanted super-thin Ge layers by RF hydrogen plasma treatment

Radio-frequency (RF) hydrogen plasma treatment, thermal annealing in a furnace, and rapid thermal annealing of high-dose P+ ion implanted p-type Ge layers have been studied by Raman scattering spectroscopy, atomic force microscopy, secondary ion mass spectrometry, electrochemical capacitance-voltage profiling, four-point probes method, and x-ray reflectometry. It was shown that low-temperature RF plasma treatment at temperature about 200 degrees C resulted in full recrystallization of amorphous Ge layer implanted by P+ ions and activation of implanted impurity up to 6.5 x 10(19) cm(-3) with a maximum concentration at the depth of about 20 nm. Rapid thermal annealing (15 s) and thermal annealing (10 min) in nitrogen ambient required considerably higher temperatures for the recrystallization and activation processes that resulted in diffusion of implanted impurity inside the Ge bulk. It was demonstrated that RF plasma treatment from the samples with front (implanted) side resulted in considerable stronger effects of recrystallization and activation as compared with the same treatment from the back (unimplanted) side. The experiment shows that nonthermal processes play an important role in enhanced recrystallization and dopant activation during the RF plasma treatment. Mechanisms of enhanced modification of the subsurface implanted Ge layer under plasma treatment are analyzed. (C) 2017 American Vacuum Society