William W. Y. Hsu

Nearly defect-free Ge gate-all-around FETs on Si substrates

The p-channel triangular Ge gate-all-around (GAA) FET with fin width (W<inf>fin</inf>) of 52nm and L<inf>g</inf> of 183nm has I<inf>on</inf>/I<inf>off</inf> =10⁵, SS= 130mV/dec, and I<inf>on</inf>=235 µA/µm at −1V. Performance can be further improved if superior gate stack than EOT=5.5 nm and D<inf>it</inf>=2×10¹² cm⁻²eV⁻¹ is used. A novel process to etch away the high defect Ge near Ge/Si interface from blanket Ge grown on SOI can solve the loading effect in the selective growth, achieve better gate control by GAA with larger effective width (W<inf>eff</inf>) than rectangular fin, and have low punch-through current through the Si substrate due to the oxide under the Ge channel and the valence band discontinuity at the Ge S/D and Si interface. By dislocation removal, the defect-free Ge channel can be formed on nothing.

High mobility high on/off ratio C-V dispersion-free Ge n-MOSFETs and their strain response

The record high peak mobility of ∼1050 cm²/V-s on (001) Ge substrate is demonstrated in NFET. High-quality Ge/GeO<inf>2</inf> interface is ensured by rapid thermal oxidation (RTO) and remote ozone plasma treatment. The best achieved subthreshold swing is 150mV/dec and the on/off ratio is 2×10⁴. The low defective n⁺/p junction produced a record high on/off ratio of 2×10⁵, an ideality factor of 1.05 and strong electroluminescence. For the first time, it is reported that the uniaxial &#60;110> tensile strain (0.08%) on &#60;110> channel direction gives the best mobility enhancement (12%) among the different strain configurations, consistent with theoretical calculation.

A convergent quadratic-time lattice algorithm for pricing European-style Asian options

Abstract Asian options are strongly path-dependent derivatives. Although efficient numerical methods and approximate closed-form formulas are available, most lack convergence guarantees. Asian options can also be priced on the lattice. All efficient lattice algorithms keep only a polynomial number of states and use interpolation to compensate for the less than full representation of the states. Let the time to maturity be partitioned into n periods. This paper presents the first O ( n 2 ) -time convergent lattice algorithm for pricing European-style Asian options; it is the most efficient lattice algorithm with convergence guarantees. The algorithm relies on the Lagrange multipliers to choose optimally the number of states for each node of the lattice. The algorithm is also memory efficient. Extensive numerical experiments and comparison with existing PDE, analytical, and lattice methods confirm the performance claims and the competitiveness of our algorithm. This result places the problem of European-style Asian option pricing in the same complexity class as that of the vanilla option on the lattice.

Electron scattering in Ge metal-oxide-semiconductor field-effect transistors

The electron mobility of n-channel metal-oxide-semiconductor field-effect transistors using Ge/GeO2/Al2O3 gate stack on (001) Ge substrates is analyzed theoretically and experimentally. Phonon scattering, Coulomb scattering, and interface roughness scattering are taken into account. The Ge peak mobility exceeding Si universal in our device by a factor of 1.3 is due to the reduction of Coulomb scattering of the interface states. As compared to Si, the faster roll-off of the Ge mobility at the effective field larger than 0.3 MV/cm is due to larger interface roughness scattering.

Efficient pricing of discrete Asian options

Asian options are popular path-dependent financial derivatives. This paper uses lattices to price fixed-strike European-style Asian options that are discretely monitored. The algorithm proposed can also be applied to floating-strike Asian options as well because fixed-strike and floating-strike Asian options are related through an equation. The discretely monitored version is usually found in practice instead of the continuously monitored version usually encountered in the literature. This paper presents the first provably quadratic-time convergent lattice algorithm for pricing fixed-strike European-style discretely monitored Asian options. It is the most efficient lattice algorithm with convergence guarantees. The algorithm relies on the Lagrange multipliers to choose the number of states for each node of the lattice. Extensive numerical experiments and comparisons with many existing numerical methods confirm the performance claims and the competitiveness of our algorithm. This result places fixed-strike European-style discretely monitored Asian options in the same complexity class as vanilla options.

Emotion Sensing for Internet Chatting: A Web Mining Approach for Affective Categorization of Events

This study proposes an emotion detection engine for real time Internet chatting applications. We adopt a Web scale text mining approach that automates the categorization of affection state of daily events. We first accumulated a huge collection of real-life entities from Web that would participate in events with a user in the chatting room. Based on the common actions between each entity and the type of the user in a chatting room session, such as boy, girl, old man and so on, each collected entity was automatically classified into different affective categories such as pleasant, provoking, grievous, and scary. During a chatting session, each sentence is first parsed using semantic roles labeling techniques to retrieve the verb and object of the event embedded in the sentence. Based on a set of manually authored emotion generation rule, the system then assigns the emotion based on the verb and the affective categories of the object. Primitive evaluations show that the precision rate of the emotion detection engine is rather satisfactory for applications that distinguish emotions of Happiness, Sadness, Anger, and Fear.

Flexible Single-Crystalline Ge p-Channel Thin-Film Transistors With Schottky-Barrier Source/Drain on Polyimide Substrates

Single-crystalline Ge p-channel thin-film transistors with Schottky-barrier source/drain (S/D) on flexible polyimide substrates are fabricated by a simple low-temperature process ( ¿ 250°C), which preserves the high mobility of Ge channel. Adhesive wafer bonding and Smart-Cut techniques were utilized to transfer the single-crystalline Ge thin film onto polyimide substrates. The Schottky-barrier S/D is formed by using Pt/n-Ge contact, showing a low hole barrier height. The device has a linear hole mobility of ~ 170 cm2·V-1·s-1 and a saturation current of ~ 1.6 ¿A/¿m at Vd = - 1.5 V for the channel length and width of 15 and 280 ¿m, respectively.

Comparative risks for cancer associated with use of calcitonin, bisphosphonates or selective estrogen receptor modulators among osteoporosis patients: a population-based cohort study

Background This population-based cohort study was to compare the risks of incident cancer in osteoporosis patients who used bisphosphonates, calcitonin or selective estrogen receptor modulators (SERMs). Methods We identified 9995 patients who were diagnosed with osteoporosis and prescribed osteoporosis drugs (bisphosphonate (n = 4675), calcitonin (n = 3993) and SERMs (n = 1327)) between 1 January 2000 and 31 December 2006 in Taiwans National Health Insurance Research Database. Date of first prescription of osteoporosis drugs was assigned as the index date. The outcome measurement was incident cancer, defined by a first-ever inpatient visit with a primary diagnosis of cancer. All patients were followed until the occurrence of cancer. For those who did not develop cancer, we censored them at 1 year after their last prescription of osteoporosis drugs. Cox proportional hazard models were used to examine the association between risk of cancer and use of calcitonin, bisphosphonates or SERMs. Results The incidence rate of cancer was 68.8, 34.0 and 29.6 per 1000 person years in the calcitonin, SERMs and bisphosphonate cohorts, respectively. Compared with bisphosphonate users, calcitonin users were associated with an increased risk of cancer (adjusted hazard ratio (HR) 2.11, 95% confidence interval (CI) 2.01-2.21, P < 0.001). SERM users were associated with an increased risk of cancer (adjusted HR 1.20, 95% CI 1.13-1.28, P < 0.001). Conclusion Our findings suggest that calcitonin is associated with an increased risk of cancer than bisphosphonate, supporting the recent warning issued by the European Medicines Agency and US Food and Drug Administration. SERMs is found to be associated with an increased risk of cancer than bisphosphonate.

Linear-time accurate lattice algorithms for tail conditional expectation

This paper proposes novel lattice algorithms to compute tail conditional expectation of European calls and puts in linear time. We incorporate the technique of prefix-sum into tilting, trinomial, and extrapolation algorithms as well as some syntheses of these algorithms. Furthermore, we introduce fractional-step lattices to help reduce interpolation error in the extrapolation algorithms. We demonstrate the efficiency and accuracy of these algorithms with numerical results. A key finding is that combining the techniques of tilting lattice, extrapolation, and fractional steps substantially increases speed and accuracy.

GEC: An Evolutionary Approach for Evolving Classifiers

Using an evolutionary approach for evolving classifiers can simplify the classification task. It requires no domain knowledge of the data to be classified nor the requirement to decide which attribute to select for partitioning. Our method, called the Genetic Evolved Classifier (GEC), uses a simple structured genetic algorithm to evolve classifiers. Besides being able to evolve rules to classify data in to multi-classes, it also provides a simple way to partition continuous data into discrete intervals, i.e., transform all types of attribute values into enumerable types. Experiment results shows that our approach produces promising results and is comparable to methods like C4.5, Fuzzy-ID3 (F-ID3), and probabilistic models such as modified Naive-Bayesian classifiers.