The use of organic materials presents a tremendous opportunity to significantly impact the functionality and pervasiveness of large-area electronics. Commercialization of this technology requires reduction in manufacturing costs by exploiting inexpensive low-temperature deposition and patterning techniques, which typically lead to lower device performance. We report a low-cost approach to control the microstructure of solution-cast acene-based organic thin films through modification of interfacial chemistry. Chemically and selectively tailoring the source/drain contact interface is a novel route to initiating the crystallization of soluble organic semiconductors, leading to the growth on opposing contacts of crystalline films that extend into the transistor channel. This selective crystallization enables us to fabricate high-performance organic thin-film transistors and circuits, and to deterministically study the influence of the microstructure on the device characteristics. By connecting device fabrication to molecular design, we demonstrate that rapid film processing under ambient room conditions and high performance are not mutually exclusive.

A fully custom designed CMOS transceiver chip for high frequency ultrasound imaging applications is described. The chip consists of nine transceiver channels with a programmable beamformer. On the chip, 8 bit 250 MS/s A/D converters digitize analog signals from the transducers and nine 3 Kbyte/channel SRAM store the digitized data for each of the nine channels. The chip was fabricated in a 0.35um standard CMOS process. The area is 26.83 mm 2 and its total power consumption is below 1.5 W at 3.3 V power supply.