On surfaces of tris-(8-hydroxyquinolate) aluminum (Alq) and tris(7-propyl-8-hydroxyquinolinato) aluminum (Al7p) thin-films, positive and negative polarization charges appear, respectively, owing to spontaneous orientation of these polar molecules. Alq is a typical electron transport material where electrons are injected from cathode. Because the polarization charge exists at the Alq/cathode interface, it is likely that it affects the electron injection process because of Coulomb interaction. In order to evaluate an impact of polarization charge on electron injection from cathode, electron only devices (EODs) composed of Alq or Al7p were prepared and evaluated by displacement current measurement. We found that Alq-EOD has lower resistance than Al7p-EOD, indicating that the positive polarization charge at Alq/cathode interface enhances the electron injection due to Coulomb attraction, while the electron injection is suppressed by the negative polarization charge at the Al7p/Al interface. These results clearly suggest that it is necessary to design organic semiconductor devices by taking polarization charge into account.

In LDMOS devices for high-voltage applications, there appears a notable fingerprint of current-voltage characteristics known as soft breakdown. Its mechanism is analyzed and modeled on LDMOS devices where a high resistive drift region exists. This analysis has revealed that the softness of breakdown, known as the expansion effect, withholding a run-away of current, is contributed by the flux of holes underneath the gate-overlap region originated by impact-ionization. The mechanism of the expansion effect is modeled and implemented into the compact model HiSIM_HV for circuit simulation. A good agreement between simulated characteristics and 2D-device simulation results is verified.

Frequency dependent properties of accumulation-mode MOS varactors, which are key elements in many RF circuits, are dominated by Non-Quasi-Static (NQS) effects in the carrier transport. The circuit performances containing MOS varactors can hardly be reproduced without considering the NQS effect in MOS-varactor models. For the LC-VCO circuit as an example it is verified that frequency-tuning range and oscillation amplitude can be overestimated by over 20% and more than a factor 2, respectively, without inclusion of the NQS effect.

We analyze the carrier dynamics in MOSFETs under low-voltage operation. For this purpose the displacement (charging/discharging) current, induced during switching operations is studied experimentally and theoretically for a 90 nm CMOS technology. It is found that the experimental transient characteristics can only be well reproduced in the circuit simulation of low voltage applications by considering the carrier-transit delay in the compact MOSFET model. Long carrier transit delay under the low voltage switching-on operation results in long duration of the displacement current flow. On the other hand, the switching-off characteristics are independent of the bias condition.

A PN junction current model for advanced MOSFETs is proposed and implemented into HiSIM2, a complete surface-potential-based MOSFET model. The model includes forward diode currents and reverse diode currents, and requires a total of 13 model parameters covering all bias conditions. Model simulation results reproduce measurements for different device geometries over a wide range of bias and temperature values.

This paper reports on the effect of switching action on the contact surfaces of earthquake disaster prevention relays. Large-scale earthquakes occur frequently in Japan and bring extensive damage with them, and fire caused by electrical equipments is one example of the serious damage which can occur. Earthquake sensors capable of maintaining a high level of reliability when earthquakes occur play an important role as a means of minimizing this damage. For this reason, we carried out observations by focusing on samples which had either been subjected to an electric current of 10 mA or 0.1 A. The samples of 10 mA exhibited low and constant contact resistance despite the addition of seismic motion, while the samples of 0.1 A samples exhibited varying contact resistance and damage on their contact spots resulting from the addition of seismic motion. The sample surfaces were then observed using an atomic force microscope (AFM) in tapping mode and a surface potential microscope (SPoM). As a result, we found that even the unused earthquake disaster prevention relay (standard sample) which had a surface lined with asperities on its parallel striations formed by irregular protrusions due to dust and other deposits. In addition, scanning the contact surface with the SPoM at the same potential revealed the occurrence of differences in surface potential which varied in response to the asperities on the striations.

Accurate extraction of the trap position in the oxide in deep-submicron MOSFET by RTN measurement has been investigated both theoretically and experimentally. The conventional equation based on the ratio of emission time and capture time ignores two effects, that is, the poly gate depletion effect and surface potential variation in strong inversion regime. In this paper, by including both of the two effects, we have derived a new equation which gives us more accurate information of the trap depth from the interface and the trap energy. With experimental result, we compare the trap depth obtained from the new equation and that of the conventional method.

The formation of single monolayer of liquid crystalline molecules, 4-n-pentyl-4-cyanobiphenyl (5CB), deposited by the evaporation method in the air, was confirmed with the surface potential measurement. The surface potential increased with the time of evaporation, and the 3- or 4-minute evaporation at a source temperature of 110 gave the saturated potential, indicating the formation of single monolayer. Single monolayer formation was also supported by the comparison of the UV-visible absorption for evaporated film with LB monolayer. Positive potentials were built at the surface, indicating that CN group faces the substrate.

The key elements of sub-100 nm MOSFET modeling for circuit simulation are accurate representation of new physical phenomena arising from advancing technologies and numerical efficacy. We summarize the history of MOSFET modeling, and address difficulties faced by conventional methods. The advantage of the surface-potential-based approach will be emphasized. Perspectives for next generations will be also discussed.

The surface potential built across vacuum deposited phthalocyanine (Pc) films on aluminum electrode was investigated by means of electro-modulation spectroscopy. The sandwich-type cells with thin air gap, which becomes a good insulator were used in order to avoid the influence of charge injection. The existence of the surface potential at the metal/organic-material interface induced 1f referenced electro-reflectance (ER) signals. As a result, the surface potential built across vacuum deposited Pc films on aluminum electrode was estimated to be 1.25 V.

The urgent tasks of MOSFET modeling for circuit simulation are easy adaptation to new physical phenomena arising for advancing technologies, and, of course, sufficient simulation accuracy. Approaches currently being pursued for developing such MOSFET models are summarized. Their capabilities for accomplishing these tasks as well as the important remaining problems are discussed. Main focus is given on the model HiSIM, the first commonly available model based on the drift-diffusion approximation developed for 0.10 µm MOSFET technology node.

It is well known that the existence of electrically resistive film layers formed on contact surfaces increases contact resistance and it causes a nonlinear relationship between voltage and current observed in a contact layer. Nonlinear distortion voltages can be detected by our sensitive detection system based on the dual frequency method when a thin film exists on the surface. In this study, multilayer films of polyimide (PI) was used as an ideal material of ultra thin film, because of electrically good insulator with simple molecular structure, to study non-linearity through metal-insulator-metal contact. The number of deposited layers between one and twenty one were formed on three types of substrates; (a) evaporated gold on a glass plate, (b) gold plate and (c) evaporated gold on gold plate, to obtain good insulating film. Where each layer of PI film has 0. 4 nanometer thickness. A pin contact was made by pressing a bent gold wire on the PI film. It is concluded that [1]; the second-order distortion voltage increases exponentially as the film thickness increases, [2]; polarity of the surface potential of PI depends on the film thickness, and that I-V characteristic depends on the polarity of the surface potential.

In the paper a problem of wave scattering from a local penetrable inhomogeneity inside a planar dielectric waveguide is studied. The surface potentials method is applied for the problem and the set of systems of BIE is obtained and analyzed from the view-point of their numerical solution. The effective numerical algorithm based on the Nyström method is proposed. The equations for a scattering diagram and mode conversion coefficients are derived.