The direct deposition of extremely thin Parylene film requires a precise control of loaded Parylene dimer, for example, 0.034g for 20 nm.Also, a model is essential to predict the deposition rate of the ultra-thin deposition. In this work, we firstly demonstrate a deposition technique that can be highly controllable and establish a model to precisely predict the thickness of the deposited Parylene film. A research of the characteristics of the so-deposited Parylene was also conducted, showing the potential usage of this technique in microelectronic devices.
In this project we invent a highly controlled molecule-level Parylene deposition technique and a unique resistive switching characteristic observed in so-deposited ultra-thin Parylene film.Get a very small deposition rate(0.08nm/g) by using an effusion micro-hole which can produce ultra-thin Parylene film.
The scheme picture of the deposition chamber is shown in Figure 1. The deposition substrate is placed inside the chamber and the micro-hole chip is glued on the cap of the chamber to seal it.
A free molecular flow model was established to describe the deposition process and could be used to predict the thickness accurately. AFM measurement showed the ultra-thin Parylene film had a nanoporous essence. A unique resistive switching phenomenon of the Parylene film with the thickness up to 40 nm was observed for the first time under a conductive-AFM scanning, which indicated the present ultra-thin Parylene deposition technique may have bright future in novel microelectronic devices.
The ratio of deposition rate between outside and inside the chamber against Knudsen number is shown in Figure 2, along with the calculated prediction of the model.
This project is sponsored by Hui-Chun Chin and Tsung-Dao Lee Chinese Undergraduate Research Endowment.
Team: Wangzhi Dai, Qiuyue Xue.
Advisor: Wei Wang