Device Characteristics of In Situ CCVD Grown Bilayer Graphene FETs at Elevated Temperatures

Abstract

In this paper we report on transfer-free fabrication of bilayer graphene field effect transistors (BiLGFETs) on oxidized silicon wafers. By means of catalytic chemical vapor deposition (CCVD) the in-situ grown BiLGFETs are realized directly on oxidized silicon substrate, whereby the number of stacked graphene layers is determined by the selected CCVD process parameters, e.g. temperature and gas mixture. BiLGFETs exhibit ultra-high on/offcurrent ratios of 10 7 at room temperature, exceeding previously reported values by several orders of magnitude. The transfer characteristic shows a pure unipolar p-type device behavior. Furthermore, when increasing the ambient temperature to 200°C, the on/off-current ratio only degrades by one order of magnitude for BiLGFETs. Besides the excellent device characteristics, the complete CCVD fabrication process is silicon CMOS compatible. This will allow a simple and low-cost integration of graphene devices for nanoelectronic applications in a hybrid silicon CMOS environment.

Transfer-Free Bilayer Graphene FETs: Application as Memory Devices

“…Since the hysteresis of BiLGFETs depends on the cycling range of the applied backgate voltage V BG while the sub-threshold slope is uniform for varied temperatures and varied cycling ranges of the backgate voltage (20,25) a suitable current voltage characteristic can be chosen to use a BiLGFET as a memory device to achieve a reading voltage of V BG = 0V. Figure 3a shows a useful current voltage characteristic for the BiLGFET with a backgate cycling range of -10V to 10V and reverse.…”

“…Additionally, the on/off-current ratio of BiLGFETs degrades only by one order of magnitude if the temperature is increased to 200°C (25). This allows the usage of bilayer graphene memory devices for applications at elevated temperatures opening up the opportunity of energy conservation due to low leakage currents.…”