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

Abstract

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

Effect of Low Temperature RF Plasma Treatment on Electrical Properties of Junctionless InGaAs MOSFETs

“…In our previous publications it has been shown that RF plasma treatment is efficient in reducing the density of fixed positive charges in SiO 2 layers and interface traps at the Si-SiO 2 interface, [9][10][11] annealing radiation-induced and ion implantation defects in metal-insulator-semiconductor (MIS) structures, 12,13 structural ordering and recrystallization of thin amorphous semiconductor layers, 14,15 low-temperature activation of implanted doping impurities in Si and Ge. [15][16][17] In this paper, we report that low-temperature RF plasma treatment in forming gas (10%H 2 +90%N 2 ) can significantly improve the electrical characteristics of n-In 0.53 Ga 0.47 As JL MOSFETs with an Al 2 O 3 gate dielectric. In particular, it provides substantial reduction of S/D resistances, an increase of the electron mobility, resulting in the strong increase of the on-state current and transconductance, reduction of the effective positive charge in the Al 2 O 3 gate dielectric, and improvement of the subthreshold slope.…”