Doping-free nanoscale complementary carbon-nanotube field-effect transistors with DNA-templated molecular lithography.

Nanoscale carbon-nanotube field-effect transistors (CNTFETs) have been a focus of recent studies in next-generation semiconductor architecture. However, in numerous CNTFETs that have been proposed, process variations, as well as measurement fluctuations, have occurred regularly, hampering the development of these devices for practical applications. Moreover, it is difficult to control the conduction polarity; the nor p-channel of an individual CNT is located on the same chip, although doping is inevitable in the implantation of complementary circuits. The fabrication of a nanoscale gap between a source and a drain has recently attracted considerable attention for electronic devices, molecular devices, and biosensors, but no CNT-FET devices with asymmetric nanogaps have been addressed. In the present study, sub-30-nm complementary doping-free CNTFET devices are fabricated in a controlled fashion usingDNAtemplated molecular lithography. This study demonstrates the polarity control of Schottky barrier (SB) FETs in a sub-30-nm region via source/drain workfunction engineering without complicated chemical doping or structural changes. This technique has many advantages for creating nanoscale highdensity as well as size-controlled CNT-FETs; it can enable these devices to be operated with polarity control between the n-channel and the p-channel. It is believed that these CNTFET devices, featuring an asymmetric nanoscale gap, will be useful for implementing complementary CNT-FET circuits with control of the nanoscale gap and the transport polarity. A highly productive framework for implementing nanoscale complementary CNT-FETs with polarity control is presented in Figure 1. Initially, 5 nm of silicon oxide was