Novel Twin-Gate Design Paves Way for Ultra Low Power 3D Devices

IME researchers have described for the first time the realisation of true 3-D integration by twin-gate metal-oxide-semiconductor field-effect transistors (MOSFET) on a single vertical Si nanowire. The devices are fabricated by CMOS processes and they exhibit >10⁶ ON/OFF ratio, tunability in drain current, as well as ‘AND’ gate functionality with 50% area reduction. The twin-gate device design is promising as an integral platform for enabling ultra low power and feature-packed 3D functional devices and circuits.

Reference:

Xiang Li et. al., “Vertically stacked and independently controlled twin-gate MOSFETS on a single Si nanowire" IEEE Electron Device Letters, Vol 32, pg 1482 - 1494, 2011

MEMS Diaphragm Offers Fresh Insights on Si Nanowires

IME researchers have described a MEMS diaphragm for characterising large compressive strain for Si nanowire piezoresistors. The diaphragm design enables Si nanowires to withstand extended compressive strain up to 1.7% without fracture, which is the highest compressive strain reported on Si nanowires to date. The new Si nanowire properties revealed in this study will bring Si nanowires a step closer to realising future MEMS sensor designs.

Reference:

Liang Lou et. al., “Characterization of silicon nanowire embedded in a MEMS diaphragm structure within large compressive strain range," IEEE Electron Device Letters, Vol 32, pg 1764 - 1766, 2011

Medical Diagnostics: Quick Blood Testing

IME researchers have developed an integrated chip for determining protein biomarkers in blood. The chip can detect three cardiac biomarkers from a fingerprick of blood in 45 mins and it is one order of magnitude higher in sensitivity than conventional enzyme linked immunosorbent assay (ELISA) method. The chip may be harnessed for point-of-care devices for rapid and sensitive diagnosis in heart patients.

Reference:

Guo-Jun Zhang et. al., “An integrated chip for rapid, sensitive, and multiplexed detection of cardiac biomarkers from fingerprick blood," Biosensors and Bioelectronics, Vol 28, pg 459 - 463, 2011

Si Optical Modulator: Low Loss, High Speed, CMOS-Compatible

IME researchers have developed a silicon optical modulator for long haul communications. By counter doping the regions outside of the active modulation region, both switching speed and modulation efficiency are minimally affected. The new silicon modulator has demonstrated a loss.efficiency figure of merit (FOM) of 19.4 dB.V, which is competitive with that of Lithium Niobate modulators (20 dB.V) that currently dominate this market segment. The new silicon modulator offers significant cost advantages as it is CMOS-compatible and allows high monolithic integration capability.

Reference:

Xiaoguang Tu et. al., “Fabrication of low loss and high speed silicon optical modulator using doping compensation method," Optics Express, Vol 19, pg 18029 - 18035, 2011

Better Pressure Sensing in a Different Mode

IME researchers have described a pressure sensor that exploits nanowire field-effect transistor principles in the subthreshold mode. Compared to its inversion operation mode, the device exhibited 1000x enhancement in signal-to-noise ratio (S/N) and 4x increased pressure sensitivity in subthreshold mode, suitable for miniature low power pressure sensors.

Reference:

Pushpapraj Singh et. al., “Gate-bias controlled sensitivity and signal-to-noise ratio enhancement in nanowire FET pressure sensor," J. Micromech. Microeng., Vol 21, 105007, 2011

FUSI: Gateway to Integration

IME researchers have designed and developed an integration scheme with a Ni fully silicided (FUSI) gate on a vertical nanowire-based metal-oxide-semiconductor field-effect transistors (MOSFET). The scheme enables nanowire devices to be incorporated into circuits as the threshold voltage (V_T) can now be tuned independently. The scheme also favours further scaling down and could be applied to produce multiple V_T devices in logic circuits under the same doping conditions.

Reference:

Z. X. Chen et. al., "Realization of Ni fully silicided gate on vertical Si nanowire MOSFETs for adjusting threshold voltage (V_T)," IEEE Electron Device Letters, Vol 32, Pg 1495 - 1497, 2011

Telecommunications: Perfecting Plastic

IME researchers have developed a pluggable large core step index plastic optical fibre (POF) for high data transmission in ultra short reach networks. The new POF uses tapered fibre tips as built-in conditioners, which together with the insertion of plug-in modules, enables transmission of 2.5 Gb/s of data – 17x faster transmission rate than conventional large core step-index POF technology. Compared to multimodal glass fibre solutions used in today’s telecom short range networks, IME’s POF offers faster data rate, increased flexibility and reduced maintenance costs for ultra short reach networks.

Reference:

J. Chandrappan et. al., “A Pluggable Large Core Step Index Plastic Optical Fiber with Built-In Mode Conditioners for Gigabit Ultra Short Reach Networks," IEEE Transactions on Advanced Packaging, Vol 33, Pg 868 - 875, 2010

Junctionless SONOS Memory: Seamless Storage

IME researchers have developed a novel SONOS memory for next generation ultra-high density memory applications. Compared to conventional planar SONOS memory cell, the absence of a junction in the cell is much more amenable to device miniaturisation as the fabrication complexity and cost are significantly reduced. The junctionless SONOS memory exhibited high on/off ratio, full memory functionality with high read/write speed and excellent reliability performance.

Reference:

Y. Sun et. al., “Junctionless Vertical-Si-Nanowire-Channel-Based SONOS Memory with 2-bit Storage per Cell," IEEE Electron Device Letters, Vol 32, Pg 725 - 727, 2011

Thermoelectric Power Generator: A Cool Chip

IME researchers have developed and demonstrated a Si nanowire based thermoelectric generator (TEG) for site-specific cooling applications. Conventional TEGs are based on bulk materials that are expensive, and are not amenable to scaling and integration with conventional electronics. Not only is the proposed TEG CMOS-compatible and scalable, it enables ready integration onto a chip level. The integrated chip size TEG could be used in miniature medical devices and high performance computing units for temperature control purpose.

Reference:

Y. Li et. al., "Chip-level Thermoelectric Power Generators Based on High-density Silicon Nanowire Array Prepared with Top-down CMOS Technology," IEEE Electron Device Letters, Vol 32, Pg 674 - 676, 2011

Optical and Electrical Interconnect: Linking Up

IME researchers have developed an integrated optical carrier with low coupling loss and good alignment tolerance for high-speed photonics applications. The proposed carrier is fabricated by a novel self alignment approach, which is straight-forward and uses standard commercially available components. Optical carriers made with conventional alignment approaches require complex process development that is time-consuming and costly. The proposed carrier exhibited a misalignment assembly tolerance of +40µm (for decrement of 0.5 dB) - competitive with that made by conventional alignment approaches but is simpler and less costly to implement.

Reference:

Teck Guan Lim et. al., "Integrated Optical Carrier for Optical/Electrical Interconnect," IEEE Transactions on Components, Packaging and Manufacturing Technology, Vol 1, Pg 125 - 132, 2011

Microfluidics for Encapsulation: Pinball Style

IME researchers have developed a novel microfluidics technique which uses micropillars to generate and encapsulate polyelectrolyte microcapsules. With the proposed technique, the deposition of three bi-layers of polyelectrolytes was demonstrated in less than 3 minutes, significantly faster than conventional bulky methods that take up to several hours. The set-up is simple in design, scalable and uses a fraction of the chemical consumption required. The new technique is suitable for biomedical and food processing applications involving drug encapsulation and food emulsification, respectively.

Reference:

Chaitanya Kantak et. al., "A 'microfluidic pinball' for on-chip generation of Layer-by-Layer polyelectrolyte microcapsules," Lab Chip, Vol 11, Pg 1030 - 1035, 2011

Achived Research Highlights