3D Investigation of 8-nm Tapered n-FinFET Model

The miniaturization has become a key word for advanced integrated circuits over the last few years. It is within this context that the fin field effect tra     

Micro-prober for wafer-level low-noise measurements in MOS devices

Low-frequency noise measurements represent an interesting investigation technique for the characterization of the quality and reliability of microelectronic materials and devices. Performing meaningful noise measurements at low and very low (f<1 Hz) frequencies, however, may be quite challenging, particularly because of the many sources of interference that superimpose on the noise signal. For this reason, packaged samples are preferred because they allow accurate shielding from the external environment, and because keeping the sample in close proximity to the low-noise biasing system and amplifier reduces microphonic and electromagnetic disturbances. Notwithstanding this, the possibility of performing low-frequency noise measurements at wafer level would be quite interesting, both because of the ease of obtaining wafer-level samples from industries with respect to packaged samples, and because this would avoid possible packaging-process induced device degradation. The purpose of this work is to demonstrate that it is, in fact, possible to design and build a dedicated probe system for performing high-sensitivity, low-frequency noise measurements on metal-oxide-semiconductor devices at wafer level.     

New insights into the relation between channel hot carrier degradation and oxide breakdown short channel nMOSFETs

In this letter, we report new findings in the relation between channel hot-carrier (CHC) degradation and gate-oxide breakdown (BD) in short-channel nMOSFETS biased at V/sub G/>V/sub D/. We observe that the time-to-BD is strongly reduced in the hot carrier regime and that although the channel hot-electron injection into the oxide occurs mainly at the drain side, stress-induced leakage current (SILC) generation and oxide BD always occur at the source side. The results of these measurements indicate that not solely the energy of the injected electrons but also the oxide electric field is determinant in the oxide BD process.     

Straightforward modeling of dynamic I–V characteristics for microwave FETs

This work presents a straightforward approach aimed at modeling the dynamic I–V characteristics of microwave active solid‐state devices. The drain‐source current generator represents the most significant source of nonlinearity in a transistor and, therefore, its correct modeling is fundamental to predict accurately the current and voltage waveforms under large‐signal operation. The proposed approach relies on using a small set of low‐frequency time‐domain waveform measurements combined with numerical optimization‐based estimation of the nonlinear model parameters. The procedure is applied to a gallium nitride HEMT and silicon FinFET. The effectiveness of the modeling procedure in terms of prediction accuracy and generalization capability is demonstrated by validation of the extracted models under operating conditions different than the ones used for the parameters estimation. Good agreement between measurements and model simulations is achieved for both technologies and in both low‐ and high‐frequency range. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:109–116, 2014.     

Investigation on TG n-FinFET Parameters by Varying Channel Doping Concentration and Gate Length

In this paper, a 3D process of a nanometric n-channel fin field-effect transistor (FinFET) is discussed and the impact of variations of the fin parameter, the gate work function, and doping concentration on device characteristics are studied using the ATLAS Silvaco device simulator. Simulation results for various gate lengths are reported and analyzed. As the quantum effects are pronounced in nanoscale devices, we have included these effects in our study and simulation. We have then compared the achieved results to classical simulations to assess their performance limits. Finally, a comparison of our results with recently published data is presented to confirm our study.     

Neural approach for temperature‐dependent modeling of GaN HEMTs

Gallium nitride high electron‐mobility transistors have gained much interest for high‐power and high‐temperature applications at high frequencies. Therefore, there is a need to have the dependence on the temperature included in their models. To meet this challenge, the present study presents a neural approach for extracting a multi‐bias model of a gallium nitride high electron‐mobility transistors including the dependence on the ambient temperature. Accuracy of the developed model is verified by comparing modeling results with measurements. Copyright © 2014 John Wiley & Sons, Ltd.     

Investigation on the non‐quasi‐static effect implementation for millimeter‐wave FET models

The present article analyzes in detail different intrinsic small‐signal models for transistors. Particular attention is devoted to the non‐quasi‐static effects, which play a crucial role at microwave and millimeter‐wave frequencies. The advantages and disadvantages of these different equivalent circuit topologies are analyzed from both theoretical and experimental standpoints. This study clearly proves that best choice among these model representations depends on the specific device technology besides the investigated frequency range. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

Laser irradiation of ZnO:Al/Ag/ZnO:Al multilayers for electrical isolation in thin film photovoltaics

Laser irradiation of ZnO:Al/Ag/ZnO:Al transparent contacts is investigated for segmentation purposes. The quality of the irradiated areas has been experimentally evaluated by separation resistance measurements, and the results are complemented with a thermal model used for numerical simulations of the laser process. The presence of the Ag interlayer plays two key effects on the laser scribing process by increasing the maximum temperature reached in the structure and accelerating the cool down process. These evidences can promote the use of ultra-thin ZnO:Al/Ag/ZnO:Al electrode in large-area products, such as for solar modules.     

How to enlarge the bandwidth without increasing the noise in OP-AMP-based transimpedance amplifier

Increasing the bandwidth without degrading the noise performance represents the main challenge in the design of transimpedance amplifiers. This paper presents a novel circuit topology for a transimpedance amplifier that allows obtaining an improved tradeoff between equivalent input noise and bandwidth with respect to the conventional approach. The effectiveness of the new topology has been demonstrated by designing and testing a prototype of a transimpedance amplifier based on the proposed topology.     

Peculiar aspects of nanocrystal memory cells: data and extrapolations

Nanocrystal memory cell are a promising candidate for the scaling of nonvolatile memories in which the conventional floating gate is replaced by an array of nanocrystals. The aim of this paper is to present the results of a thorough investigation of the possibilities and the limitations of such new memory cell. In particular, we focus on devices characterized by a very thin tunnel oxide layer and by silicon nanocrystals formed by chemical vapor deposition. The direct tunneling of the electrons through the tunnel oxide, their storage into the silicon nanocrystals, and furthermore, retention, endurance, and drain turn-on effects, well-known issues for nonvolatile memories, are all investigated. The cell can be also programmed by channel hot electron injection, allowing the possibility to multibit storage. The suppression of the drain turn-on and the possibility of using this cell for multibit storage give us a clear evidence of the distributed nature of the charge storage.