Lo, Hsi-Wen (2009) Thin film silicon for implantable electronics. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-09242008-151715
The implantable electronic systems have changed our life greatly and provided crucial support for people who previously could not live an independent life otherwise. However, current implantable electronic systems are based on technologies more than 50 years old and more medical problems require advanced implantable electronic systems with small form factors and multiple electrodes. This work explores and evaluates possible alternatives of implantable electronic systems.
Parylene, a widely used MEMS/CMOS process compatible material, is the cornerstone of this work. Parylene has been an ISO10933 and USP Class VI certiﬁed biocompatible material. Parylene serves as the substrate and protective coating of the implantable electronic systems developed in this work.
Thin ﬁlm pentacene is studied in this work and thin ﬁlm pentacene transistors are developed. The thin ﬁlm pentacene transistor uses Parylene as the ﬂexible substrate, the gate insulator and the protective coating. Studies of parylene surface are carried out. And based on this study, pentacene hole mobility is improved using spin-cast smoothing layers and top-contact conﬁgurations. To evaluate the long term reliability and stability of the thin ﬁlm pentacene transistors, saline soaking tests are performed. The results are less than satisfactory.
In addition, thin ﬁlm amorphous silicon is studied and thin ﬁlm amorphous silicon transistors are developed. This thin-ﬁlm amorphous silicon uses Parylene HT®, a Parylene variant with high temperature stability, as the ﬂexible substrate. To evaluate the long term reliability and stability of the thin ﬁlm amorphous silicon transistor, room temperature saline soaking tests and 80◦ C accelerated saline soaking tests are carried out. The thin ﬁlm amorphous silicon transistors show excellent stability in saline soaking. The thin ﬁlm amorphous silicon transitor shows no degradations after more than 90 days in 80◦ C saline solution.
In summary, thin ﬁlm pentacene transistors and thin ﬁlm amorphous silicon transistors are developed and their performances are optimized. The long-term stability and reliability of these transistors are evaluated via saline soaking tests. While thin ﬁlm pentacene transistors show only less than satisfactory results, thin ﬁlm amorphous silicon transistors exhibit stable and reliable performances.
|Item Type:||Thesis (Dissertation (Ph.D.))|
|Subject Keywords:||amorphous silicon; implant; pentacene; thin film transistor|
|Degree Grantor:||California Institute of Technology|
|Division:||Engineering and Applied Science|
|Major Option:||Electrical Engineering|
|Thesis Availability:||Restricted to Caltech community only|
|Defense Date:||24 September 2008|
|Default Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Imported from ETD-db|
|Deposited On:||07 Oct 2008|
|Last Modified:||26 Dec 2012 03:02|
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