Using Ultrathin Parylene Films as an Organic Gate Insulator in Nanowire Field-Effect Transistors

作者：Gluschke J G; Seid J; Lyttleton R W; Carrad D J; Cochrane J W; Lehrnann S; Samuelson L; Micolich A P^*

来源：Nano Letters, 2018, 18(7): 4431-4439.

DOI：10.1021/acs.nanolett.8b01519

• Parylene
• nanowires
• gate-all-around
• field-effect transistor
• organic gate insulator

We report the development of nanowire field-effect transistors featuring an ultrathin parylene film as a polymer gate insulator. The room temperature, gas-phase deposition of parylene is an attractive alternative to oxide insulators prepared at high temperatures using atomic layer deposition. We discuss our custom-built parylene deposition system, which is designed for reliable and controlled deposition of <100 nm thick parylene films on III-V nanowires standing vertically on a growth substrate or horizontally on a device substrate. The former case gives conformally coated nanowires, which we used to produce functional a-gate and gate-all-around structures. These give subthreshold swings as low as 140 mV/dec and on/off ratios exceeding 103 at room temperature. For the gate-all-around structure, we developed a novel fabrication strategy that overcomes some of the limitations with previous lateral wrap-gate nanowire transistors. Finally, we show that parylene can be deposited over chemically treated nanowire surfaces, a feature generally not possible with oxides produced by atomic layer deposition due to the surface "self-cleaning" effect. Our results highlight the potential for parylene as an alternative ultrathin insulator in nanoscale electronic devices more broadly, with potential applications extending into nanobioelectronics due to parylene's well established biocompatible properties.

• 出版日期2018-7