A practical operational amplifier circuit is formed using thing film transisters. An operational amplifier circuit is formed by thin film transistors formed on a quartz substrate wherein cumulative distribution of mobilities of the n-channel type thin film transistors becomes 90% or more at 260 cm2/Vs...http://www.google.ca/patents/US7759681?utm_source=gb-gplus-sharePatent US7759681 - Thin film circuit
