Fabrication method of carbon nanotube transistor device realized by etching self-alignment process

Abstract

The invention discloses a method for manufacturing a carbon nanotube transistor device realized by an etching self-alignment process, which comprises the following steps: 1) arranging a carbon nanotube film on a substrate; 2) arranging a layer of metal film on the carbon nanotube film; 3) The source region, the drain region and the channel region are divided on the metal film, and the metal film and carbon nanotube film outside the above regions are removed; 4) The gate region is divided on the channel region; 5) The channel region is etched, and a gap is formed between the channel region and the source metal electrode region, and between the channel region and the drain metal electrode region, as the gap between the gate and the source and drain electrodes; 6 ) preparing a gate dielectric on the channel region; 7) covering the gate metal on the gate dielectric, thereby completing the preparation of the carbon nanotube FET device. The invention simplifies the device preparation steps, improves the ohmic contact, and comprehensively improves the device performance of the carbon nanotube field effect transistor.

Description

technical field [0001] The invention belongs to the technical field of microelectronics. Background technique [0002] The unique one-dimensional quantum transport properties of carbon nanotube materials enable them to have ultra-high intrinsic carrier mobility (up to 100,000 cm 2 / Vs) and saturation drift speed (>10 7 cm / s), which is an ideal material for realizing radio frequency devices. Carbon nanotubes have a mean free path of up to several hundred micrometers, and can achieve ballistic transport at room temperature and at achievable device channel lengths, exhibiting high carrier mobility and saturation drift velocity. The quasi-one-dimensional structure and nano-scale diameter of carbon nanotubes make their intrinsic capacitance extremely small. Within the allowable range of the process, the quantum capacitance limit can be approached, thereby obtaining excellent gate control performance. Carbon nanotube-based RF field-effect transistors have great potential in ...

AI Technical Summary

Problems solved by technology

For organic substances such as photoresist, it is usually removed by soaking in acetone and oxygen plasma etching process, but due to the extremely fine structure of carbon nanotubes, ultrasonic assistance cannot be used, and oxygen plasma will also cause damage to carbon nanotubes. Damage or even etching, so pollutants such as photoresist, electron beam writing glue or other impurities are extremely difficult to remove, and a small amount of residue adheres to the surface of carbon nanotubes

In addition, strong oxidizing acids will break the C-C bond and introduce defects on the carbon nanotubes

Impurity residues, defects, and substrate effects on the surface of carbon nanotubes will significantly damage the performance of carbon nanotube field effect transistors, mainly reflected in: (1) impurity residues remain between the carbon nanotubes and the source-drain contact metal electrodes between, reduce the source / drain ohmic contact performance of the device, lead to an increase in the parasitic resistance of the device, and directly damage the performance of the device; (2) impurity residues and defects on the carbon nanotube channel significantly increase the probability of carrier scattering in the carbon nanotube channel, Significantly lower carrier mobility

Especially because of the quasi-one-dimensional structure of carbon nanotubes, there is only one atomic layer. When carriers are transported on the walls of carbon nanotubes, they are more likely to be scattered by interfacial impurities than those transported inside traditional bulk materials. Therefore, the surface of carbon nanotubes Impurity contamination or defects will lead to a significant reduction in carrier mobility in the device channel, which greatly affects device performance; (3) the oxygen plasma etching method for assisting deglue in the standard semiconductor device manufacturing process, and strong oxidizing properties such as nitric acid The substance will cause damage to the carbon nanotube itself, increase the defect of the carbon nanotube, and the defect on the channel can become the scattering center of the carrier, which also leads to a decrease in the carrier mobility; (4) carbon nanotube and substrate material There is an interface scattering effect between them, and also due to the quasi-one-dimensional structure of carbon nanotubes, the impact of interface scattering effect on the carrier transport in the channel of carbon nanotubes is more significant than that on the channel of traditional bulk materials, causing the carrier The carrier mobility is reduced, and the overall performance of the device is degraded

Images