Filed: Ali Afzali-Ardakani, Yorktown Heights, N.Y.; Juan Ayala-Esquilin, San Jose, Calif.; Bodil E. Braren, Hartsdale; Shahrokh Daijavad, Peekskill, both of N.Y.; Elizabeth Foster, Friendsville, Pa.; James L. Hedrick, Jr., Oakland, Calif.; Jeffrey C. Hedrick, Peekskill, N.Y.; Rodney T. Hodgson, Ossining, N.Y.; Ashit A. Mehta, Vestal, N.Y., Steven E. Molis, Brewster, N.Y.; Jane M. Shaw, Ridgefield, Conn.; Stephen L. Tisdale, Vestal, N.Y.; Alfred Viehbeck, Fishkill, N.Y.

The gate bias dependence of the field-effect mobility in pentacene-based insulated gate field-effect transistors (IGFETs) was interpreted on the basis of the interaction of charge carriers with localized trap levels in the band gap. This understanding was used to design and fabricate IGFETs with mobility of more than 0.3 square centimeter per volt per second and current modulation of 10(5), with the use of amorphous metal oxide gate insulators. These values were obtained at operating voltage ranges as low as 5 volts, which are much smaller than previously reported results. An all-room-temperature fabrication process sequence was used, which enabled the demonstration of high-performance organic IGFETs on transparent plastic substrates, at low operating voltages for organic devices.

Negative photoresists are materials that become insoluble in developing solutions when exposed to optical radiation. They were the first systems used to pattern semiconductor devices, and still comprise the largest segment of the photoresist industry because they are widely used to define the circuitry in printed wiring boards. However, the current use of negative resists in the semiconductor industry has been limited by past difficulties in achieving high-resolution patterns. Recent advances in the chemistry of negative-resist systems, however, have provided materials with wide processing latitude and high resolution that are used to manufacture IBM's advanced CMOS devices and to achieve high-aspect-ratio patterns for micromachining applications. This paper provides an overview of the history and chemistry of negative-resist systems and their development in IBM.