|
Initiative for Nanoscale Materials and Processes, INMP Phase 2(Industry Group) Principal Investigators: Yoshio Nishi, Paul McIntyre (MSE) and Krishna Saraswat (EE) This project is aimed at fundamental understandings of metal gate/high K dielectrics/ high mobility channel structure at atomic/molecular levels to provide in-depth knowledge and discovery for ITRS 32nm node and beyond CMOS technology. Nishi group・s contribution to this Initiative includes metal gate work function engineering and fundamental study for metal-insulator/semiconductor interfaces.? Metal/metal bilayer structures can be used to adjust the gate electrode work function over a 1eV range for a variety of metals by controlling the thickness of the bottom metal layer. ?Current year・s focus is to investigate ：variability； of small geometry metal gate high k CMOS which would be rather sensitive function of crystal orientation of nanosized metal grain on top of high k dielectrics.?? Threshold voltage stability and reliability under stress are also under investigation. Nonvolatile Memory Technology Research Initiative, NMTRI (Industry Group) Principal Investigators: Yoshio Nishi, Paul McIntyre, Krishna Saraswat, Philip Wong, Simon Wong, Yi Cu Scope: This initiative for non-volatile memory research aims at dealing with challenges of increasing needs for embedded memory with high density and low cost with power minimization by forming an interdisciplinary team of faculty, staff and students to look into technical feasibility at the device level, circuit/system level as well as develop a fundamental understanding for a variety of new non-volatile memory phenomena, materials and processes.? We propose several connected research themes showing (i) how barrier engineering can improve flash and ferroelectric devices (ii) how scalable are the various resistance switch materials and mechanisms (iii) how nanowire diodes can be integrated with resistive switches in crosspoint arrays (iv) how cell and circuit innovations can improve performance and (v) how bulk and interface effects control reliability and endurance.? The scope of the initiative is for 5 years aiming at possible infusion into the 32-21nm ITRS nodes and beyond. Nishi group・s contribution will be in the area of resistance change memory with metal oxides such as TiO2, Al2O3, and metal sulfides such as CuS, ZnS/CdS as the switching materials, and look into physical mechanism for switching, endurance, retention.
III-V FET on Silicon for High Performance Digital Logic (Intel CIS FMA) Principal investigators: Yoshio Nishi (EE), Paul McIntyre (MSE), Krishna Saraswat (EE), Philip Wong (EE) Scope: This project is to explore III-V semiconductors for possible use as the channel of filed effect transistors for high speed performance digital logic circuits.? Research includes both experimental and theoretical studies of quantum confined carrier transport in III-V channel, high k dielectrics on III-V semiconductor and interfaces, metal gate work function engineering, the band to band tunneling and source/drain electrodes engineering. Nishi Group・s contribution is mainly on the high k-III-V interface characterization and work function engineering leveraged from the INMP phase 1 research. High resolution XPS to understand detailed mechanism of sulfur passivation of HfO2/GaAs, GaInAs interfaces, and ESR study of such interfaces are in progress. Germanium Surface Clean in Environmentally Benign Semiconductor Manufacturing (SRC, industry) Principal Investigator: Yoshio Nishi Team: Masaharu Kobayashi, Jim McVittie This project is aiming at understanding of the nature of germanium surface contaminations and develops cleaning technology for improved performance of germanium based MOS devices with environmentally benign combinations for chemistry and processes. Ab-Initio Modeling/Simulation Research on Interfaces Principal Investigator:, Yoshio Nishi Ab initio calculations based on density functional theory have been employed to study metal-oxide and metal-semiconductor interfaces. For the metal-oxide project: valence band offsets, interface charge density distributions and separation energies are determined, the ultimate goal being to establish the variation range of the metal effective work function due to chemical reactions and defects. Our interface models are composed of metals with different vacuum work functions (e.g. Al, Ni, W, Nb, etc.) and their bilayers deposited on SiO2 and HfO2. Oxygen rich and deficient interfaces are included in the database. We find that the work function of metals on oxides is significantly influenced by the interface configurations and by the particular bonding pattern at the interface. A universal linear relationship between the interface dipoles of metal-oxide interfaces and the effective work function has been established. For the metal- semiconductor interfaces chemical and electrical properties were investigated for a model NiSi2/Si interface. It has been found that Y, Ti, Sc and V incorporation in the vicinity of the interface has a strong effect on the interfacial charge transfer and strongly affects the Schottky barrier height.
Nanoparticle Based Light Emitting Devices (Toshiba FMA) Principal Investigators: Yoshio Nishi, Jelena Vuckovic Scope: Light emission from quantum confined nanoparticles has attracted significant attention in the past several years as it suggests possible replacement of chemical dies and may also provide alternative solution to light sources for a variety of applications ranging from light emitting devices, displays, on-chip optical interconnects for integrated circuits, on top of scientific interest in manipulating band structures of solid state materials through quantum confinement effects.???
New Diagnostic Imaging and Sensing (Canon CISFMA, and Canon Sponsored Research) Principal Investigators: Yoshio Nishi (EE), Pierre Butrus Khuri-Yakub(EE), Paul McIntyre (MSE), Scope: This project consists of two major components: One is to explore opportunities for non-invasive diagnostic imaging by using photoacoustic imaging by using a combination of photoacoustic stimulated emission of ultra sounds from functionalized nanoparticles detected by two dimensional ultra-sound sensors, and the other is to investigate bio-sensing of charged species in bio-fluid by using field effect electronic devices as sensing elements.? This is a broad disciplined project involving School of Engineering and School of Medicine faculty members. BioFETteam: Kozar Baghbari Parizi, Yoshio Nishi
Solution Processed Organic Transistors and Circuits on Flexible Substrate for Large-Area Electronic-Paper Display Backplane: (Toshiba CIS CR/FMA)
Team: Zihong Liu Scope: This research project is focused on an emerging area of organic molecular semiconductor/carbon-nanotube (CNT) network based flexible electronics, specifically, solution-processed organic semiconductor/CNT-network transistors and integrated circuits on plastic substrates for large-area/ubiquitous flexible electronics, such as electronic papers, flexible displays, bendable scanners, wearable sensors and printed Radio Frequency Identification (RFID) tags, etc. Currently we have successfully established and statistically optimized novel organic materials as the dielectric, semiconductor and electrode for the high-performance solution-processed flexible transistors based on a newly-developed solution-shearing processing method. Ongoing work is to develop a low-cost, roll-to-roll compatible solution process for manufacturing of large-area flexible integrated circuits/display backplanes and demonstrate prototypes based on high-performance solution-processed organic semiconductor and CNT-network thin-film transistors.
Lateral Nanoconcentrator Nanowire Multijunction Photovoltaic Cells (GCEP) Principal Investigators: H.-S. Philip Wong (EE), Peter Peumans (EE), Mark L. Brongersma (MSE) and Yoshio Nishi (EE) A novel type of multijunction photovoltaic cell that addresses the shortcomings of traditional multijunction cells and could lead to a technology that satisfies all the requirements set forth in the RFP. Our approach uses lateral arrays of semiconductor nanowires (NWs) of various bandgaps as the elements that convert optical energy into electrical energy. To achieve spectral splitting needed for efficient multijunction operation, the NWs are located on top of a specifically designed metal nanostructure that acts as (1) an array of electrodes to the nanowires, a (2) lateral spectral splitter, and (3) as a lateral concentrator.
Low Temperature Process for Vertical Transistor for Three-Dimensional Integration (TEL Gift Fund) Principal Investigator: Yoshio Nishi New high density/low energy plasma processing tool, SPA, (donation by TEL) has unique characteristics for low temperature oxidation with isotropic and low interface states density on a variety of crystal orientations of silicon.?? This research project looks into feasibility of vertical nanopillar devices using the SPA tool which would open up possibility of 3-D devices and integration, and even extend possibility to germanium devices.? Fundamental Studies of Resistance-Change Properties in Transition Metal Oxides (Hynix Gift Fund) Principal Investigator: Yoshio Nishi The purpose of this research is to investigate the switching mechanism of resistance change memory to much in-depth by both theoretical and experimental approaches coupled together through thorough characterizations of switching phenomena, endurance, retention and their degradation mechanism, followed by further evaluation at memory array level.
|
