The ellipsometric measurement of refractive indexes for films less than 50 nm thick is of dubious quality due to the significance of the size of random errors relative to the accuracy required to extract reliable index values from the measurements. In this study the various errors are quantitatively assessed as a function of the film thickness, and then compared with experimental data obtained from differently prepared silicon dioxide films on silicon. The new results confirm previous work that shows higher refractive indexes for thinner films. Transmission electron microscopy confirms the results. Graded and discrete layer models are compared.

Implantation of Si in does of 1015–1016 cm−2 into dry thermal oxides on silicon wafers produces a three-state MOS memory device. For both positive- and negative-going traps, gate voltage stress up to ±10 MV/cm−1 generates stable (±) oxide charge near the gate and (∓) charge near the substrate. Electron paramagnetic resonance (EPR) measurement on corona-field (≤11 MV/cm) stressed oxides reveals E′ centers in regions of positive charge, which may be recycled between the EPR-visible (+) state and the invisible neutral state. The correspondence of charge and EPR indicates a composite or Feigl-Fowloer-Yip E′ center, O3 3/4 Si:...+Si 3/4 O3, arising from nonstoichiometric Si fused into the SiO2 lattice. Upon trapping an electron, the center rebonds to yield O3 3/4 SiSi 3/4 O3. The charging parameters of the E′ center suggest tunneling of an electron from the (0→+) state, and are consistent with the theoretical prediction of the energy level and Franck–Condon relaxation. The three types of E′ centers observed in this and related studies are compared with the E′α, Eβ and E′γ variants of bulk amorphous silica.

The adaptation of semiconductor technologies for biological applications may lead to a new era of inexpensive, sensitive, and portable diagnostics. At the core of these developing technologies is the ion-sensitive field-effect transistor (ISFET), a biochemical to electrical transducer with seamless integration to electronic systems. We present a novel structure for a true dual-gated ISFET that is fabricated with a silicon-on-insulator (SOI) complementary metal-oxide-semiconductor process by Taiwan Semiconductor Manufacturing Company (TSMC). In contrast to conventional SOI ISFETs, each transistor has an individually addressable back-gate and a gate oxide that is directly exposed to the solution. The elimination of the commonly used floating gate architecture reduces the chance of electrostatic discharge and increases the potential achievable transistor density. We show that when operated in a "dual-gate" mode, the transistor response can exhibit sensitivities to pH changes beyond the Nernst limit. This enhancement in sensitivity was shown to increase the sensor's signal-to-noise ratio, allowing the device to resolve smaller pH changes. An improved resolution can be used to enhance small signals and increase the sensor accuracy when monitoring small pH dynamics in biological reactions. As a proof of concept, we demonstrate that the amplified sensitivity and improved resolution result in a shorter detection time and a larger output signal of a loop-mediated isothermal DNA amplification reaction (LAMP) targeting a pathogenic bacteria gene, showing benefits of the new structure for biosensing applications.

MEMS technology development and MEMS manufacturing activities at TSMC are presented. Two models for process development, i.e. customer product/process "phase-in" and internally developed "platform" are discussed. The latter is a TSMC-MEMS platform for motion sensors and other devices.