S. P. McAlister

Small-Subthreshold-Swing and Low-Voltage Flexible Organic Thin-Film Transistors Which Use HfLaO as the Gate Dielectric

Pentacene organic thin-film transistors (OTFTs) with a high-kappa HfLaO dielectric were integrated onto flexible polyimide substrates. The pentacene OTFTs exhibited good performance, such as a low subthreshold swing of 0.13 V/decade and a threshold voltage of -1.25 V. The field-effect mobility was 0.13 cm2/Vmiddots at an operating voltage as low as only 2.5 V. These characteristics are attractive for high-switching-speed and low-power applications.

Very high-density (23 fF//spl mu/m/sup 2/) RF MIM capacitors using high-/spl kappa/ TaTiO as the dielectric

A very high density of 23 fF//spl mu/m/sup 2/ has been measured in RF metal-insulator-metal (MIM) capacitors which use high-/spl kappa/ TaTiO as the dielectric. In addition, the devices show a small reduction of 1.8% in the capacitance, from 100 kHz to 10 GHz. Together with these characteristics the MIM capacitors show low leakage currents and a small voltage-dependence of capacitance at 1 GHz. These TaTiO MIM capacitors should be useful for precision RF circuits.

Improved High-Temperature Leakage in High-Density MIM Capacitors by Using a TiLaO Dielectric and an Ir Electrode

We have fabricated high-kappa TaN/Ir/TiLaO/TaN metal-insulator-metal capacitors. A low leakage current of 6.6 times 10-7 A/cm2 was obtained at 125degC for 24-fF/mum2 density capacitors. The excellent device performance is due to the combined effects of the high-kappa TiLaO dielectric, a high work-function Ir electrode, and large conduction band offset.

Integrated antennas on Si with over 100 GHz performance, fabricated using an optimized proton implantation process

We have improved the performance of integrated antennas on Si for possible application in wireless communications and wireless interconnects. For practical VLSI integration, we have reduced the antenna size and optimized the proton implantation to a low energy of /spl sim/4 MeV with a depth of /spl sim/175 /spl mu/m. To avoid any possible contamination, the ion implantation is applied after device fabrication. Excellent performance such as very low RF power loss up to 50 GHz, record high 103 GHz antenna resonance, and sharp 5 GHz bandwidth have been achieved.

Low Subthreshold Swing HfLaO/Pentacene Organic Thin-Film Transistors

We have integrated a high-kappa HfLaO dielectric into pentacene-based organic thin-film transistors. We measured good device performance, such as a low subthreshold swing of 0.078 V/dec, a threshold voltage of -1.3 V, and a field-effect mobility of 0.71cm2/ Vldrs . This occurred along with an ON-OFF state drive current ratio of 1.0 times 105, when the devices were operated at only 2 V. The performance is due to the high gate-capacitance density of 950 nF/cm2 that is given by the HfLaO dielectric, which is achieved at an equivalent oxide thickness of only 3.6 nm with a low leakage current of 5.1 times 10-7 at 2 V.

High-performance poly-silicon TFTs incorporating LaAlO/sub 3/ as the gate dielectric

We have integrated a high-/spl kappa/ LaAlO/sub 3/ dielectric into low-temperature poly-Si (LTPS) thin-film transistors (TFTs). Good TFT performance was achieved-such as a high drive current, low threshold voltage and subthreshold slope, as well as an excellent on/off current ratio and high gate-dielectric breakdown field. This was achieved without hydrogen passivation or special crystallization steps. The good performance is related to the high gate capacitance density and small equivalent-oxide thickness provided by the high-/spl kappa/ dielectric.

High-/spl kappa/ Ir/TiTaO/TaN capacitors suitable for analog IC applications

We have developed novel high-/spl kappa/ Ir/TiTaO/TaN capacitors which have high-capacitance density (10.3 fF//spl mu/m/sup 2/), small leakage current at 2 V (1.2/spl times/10/sup -8/ A/cm/sup 2/), and low voltage linearity of the capacitance (89 ppm/V/sup 2/). These excellent results meet the ITRS roadmap requirements for precision analog capacitors for the year 2018. The good performance is due to the very high /spl kappa/ (45) achieved in the TiTaO dielectric and the high work-function (5.2 eV) provided by the Ir electrode.

A flexible organic pentacene nonvolatile memory based on high-κ dielectric layers

We report a pentacene thin film transistor nonvolatile memory fabricated on a flexible polyimide substrate. This device shows a low program/erase voltage of 12 V, a speed of 1/100 ms, an initial memory window of 2.4 V, and a 0.78 V memory window after 48 h. This has been achieved by using a high-κ dielectric as charge trapping, blocking, and tunneling gate insulator layers.

RF passive devices on Si with excellent performance close to ideal devices designed by electro-magnetic simulation

High quality RF inductors, very low loss and noise CPW and microstrip lines, advanced broad and narrow band filters, and ring resonators have been achieved on Si substrates, using an optimized proton implantation process. The RF performance up to 100 GHz is close to that for ideal devices designed by EM simulation for lossless substrates.

Use of a High-Work-Function Ni Electrode to Improve the Stress Reliability of Analog

We have studied the stress reliability of low-energy-bandgap high- metal-insulator-metal capacitors under constant voltage stress. By using a high-work-function Ni electrode (5.1 eV), we reduced the degrading effects of stress on the capacitance variation (DeltaC/C), the quadratic voltage coefficient of capacitance (VCC-alpha), and the long-term reliability, in contrast with using a TaN. The improved stress reliability for the Ni electrode capacitors is attributed to a reduction of carrier injection and trapping.