Carbon Nanotube Based Radio Frequency Transistors for K-Band Amplifiers

Abstract

Owing to the combination of high carrier mobility and saturation velocity, low intrinsic capacitance, and excellent stability, the carbon nanotube (CNT) has been considered as a perfect semiconductor to construct radio frequency (RF) fieldeffect transistors (FETs) and circuits with an ultrahigh frequency band. However, the reported CNT RF FETs usually exhibited poor real performance indicated by the as-measured maximum oscillation frequency (f max ), and then the amplifiers, which are the most important and fundamental RF circuits, suffered from a low power gain and a low frequency band. In this work, we build RF transistors on solution-derived randomly orientated CNT films with improved quality and uniformity. The randomly orientated CNT film FETs exhibit the record as-measured maximum f max of 90 GHz, demonstrating the potential for over 28 GHz (at least one-third of 90 GHz) 5G mmWave (frequency range 2) applications. Benefiting from the large-scale uniformity of CNT films, FETs are designed and fabricated with a large channel width to present low internal resistance for the standard 50 Ω impedance matching guide line, which is critical to construct an RF amplifier. Furthermore, we first demonstrate amplifiers with a maximum power gain up to 11 dB and output third-order intercept point (OIP3) of 15 dBm, both at the K-band, which represents the record of a CNT amplifier and is even comparable with a commercial amplifier based on III−V RF transistors.

Aligned Carbon Nanotubes-Based Radiofrequency Transistors for Amplitude Amplification and Frequency Conversion at Millimeter Wave Band

“…The power gain is still over 3 dB even operating above 40 GHz. It is worth noting that 7 dB of power gain directly obtained by S 21 is apparently lower than previously reported works ,, with load pull results but power gain in this work is actual performance which could be directly acquired in RF circuits with standard 50 Ω impedance no need on/off-chip matching network. We benchmark power gain with bandwidth of ACNTs based RF amplifiers with previously reported ones based on nanomaterials ,,, as shown in Figure d.…”

“…In a typical RF system, the amplitude of high-speed signals should be amplified by an amplifier for follow-up operation, and the frequency should be converted up for transmission and down for baseband processing usually by mixer. Although lots of CNT based RF devices and progress were reported on cutoff frequency/speed, ,,− few works discussed amplification and conversion. Only in ref was the ACNTs based RF amplifier demonstrated with gain measured by a load pull system, but the operating frequency was only 18 GHz.…”

Carbon Nanotube Radiofrequency Transistors With f T/f MAX of 376/318 GHz

“…Due to the high f MAX of over 300 GHz, ACNT based RF transistors can be used to build RF amplifiers with high bandwidth and higher gain. We investigated the RF amplifiers using a load-pull setup mentioned in previous work [13], [14]. Our champion amplifier with 35 nm gate length has a maximum power gain of 26.4 dB, 25.3 dB and 24.1 dB (18.1 dB, 15.9 dB, and 13.2 dB) at 8 GHz, 12 GHz and 18 GHz respectively as shown in Fig.…”

Terahertz metal-oxide-semiconductor transistors based on aligned carbon nanotube arrays

“…4e). Therefore, the development of gate technology in CNT RF transistors has evolved from an ordinary gate 19,27 to T-gate 22 and now to Y-gate in this work, which boosts the f MAX of CNT MOS FETs beyond 1 THz.…”