Implementation of Ambipolar Polysilicon Thin-Film Transistors with Nickel Silicide Schottky Junctions by Low-Thermal-Budget Microwave Annealing

Abstract

In this study, the efficient fabrication of nickel silicide (NiSix) Schottky barrier thin-film transistors (SB-TFTs) via microwave annealing (MWA) technology is proposed, and complementary metal-oxide-semiconductor (CMOS) inverters are implemented in a simplified process using ambipolar transistor properties. To validate the efficacy of the NiSix formation process by MWA, NiSix is also prepared via the conventional rapid thermal annealing (RTA) process. The Rs of the MWA NiSix decreases with increasing microwave power, and becomes saturated at 600 W, thus showing lower resistance than the 500 °C RTA NiSix. Further, SB-diodes formed on n-type and p-type bulk silicon are found to have optimal rectification characteristics at 600 W microwave power, and exhibit superior characteristics to the RTA SB-diodes. Evaluation of the electrical properties of NiSix SB-TFTs on excimer-laser-annealed (ELA) poly-Si substrates indicates that the MWA NiSix junction exhibits better ambipolar operation and transistor performance, along with improved stability. Furthermore, CMOS inverters, constructed using the ambipolar SB-TFTs, exhibit better voltage transfer characteristics, voltage gains, and dynamic inverting behavior by incorporating the MWA NiSix source-and-drain (S/D) junctions. Therefore, MWA is an effective process for silicide formation, and ambipolar SB-TFTs using MWA NiSix junctions provide a promising future for CMOS technology.

High-Performance Bidirectional Chemical Sensor Platform Using Double-Gate Ion-Sensitive Field-Effect Transistor with Microwave-Assisted Ni-Silicide Schottky-Barrier Source/Drain

“…After depositing a 150-nm-thick Ni layer using an electron beam evaporator, Ni was selectively left in the S/D region through a lift-off process. Then, using a 600 W MWI source for 2 min in an N 2 ambient, Ni-silicide, which is a key material for bipolar switching, was formed [25]. Unreacted Ni was removed using a sulfur peroxide mixture (SPM) for 10 min.…”