Showing papers by "Robert Henderson published in 2007"

A Single Photon Avalanche Diode Implemented in 130-nm CMOS Technology

Abstract: We report on the first implementation of a single photon avalanche diode (SPAD) in 130 nm complementary metal-oxide-semiconductor (CMOS) technology. The SPAD is fabricated as p+/n-well junction with octagonal shape. A guard ring of p-well around the p+ anode is used to prevent premature discharge. To investigate the dynamics of the new device, both active and passive quenching methods have been used. Single photon detection is achieved by sensing the avalanche using a fast comparator. The SPAD exhibits a maximum photon detection probability of 41% and a typical dark count rate of 100 kHz at room temperature. Thanks to its timing resolution of 144 ps full-width at half-maximum (FWHM), the SPAD has several uses in disparate disciplines, including medical imaging, 3D vision, biophotonics, low-light illumination imaging, etc.

Anodic Ta2O5 for CMOS compatible low voltage electrowetting-on-dielectric device fabrication

Abstract: This paper reports a CMOS compatible fabrication procedure that enables ElecroWetting On Dielectric (EWOD) technology to be post-processed on foundry technology. With driving voltages less than 15 V it is believed to be the lowest reported driving voltage for any material system compatible with post-processing on integrated circuits. The process architecture uses anodically grown tantalum pentoxide as the pinhole free high dielectric constant insulator with the overlying 16 nm layer of Teflon-AFreg, which provides the hydrophobic surface upon which droplets can be manipulated. This stack provides a very robust dielectric, which maintains a sufficiently high capacitance per unit area for effective operation at the lower voltage favoured by more standard CMOS technology. The paper demonstrates that the sputtered tantalum layer can be integrated with the aluminium (or copper) interconnect of foundry CMOS processes by standard microfabrication techniques.

A 130-nm CMOS single-photon avalanche diode

Abstract: The first implementation of a single photon avalanche diode (SPAD) is reported in 130nm CMOS technology. The SPAD is fabricated as p+/nwell junction with octagonal shape. Premature edge breakdown is prevented through a guard ring of p-well around the p+ anode. The dynamics of the new device are investigated using both active and passive quenching methods. Single photon detection is achieved by sensing the avalanche using a fast comparator. The SPAD exhibits a maximum photon detection probability of 41% and a typical dark count rate of 100kHz at room temperature. Thanks to its timing resolution of 144ps (FWHM), the SPAD can be used in disparate disciplines, including medical imaging, 3D vision, biophotonics, low-light-illumination imaging, etc.

CMOS-integrated flip-chip, micro-pixel InGaN LED arrays for on-chip microfluorimetry

Abstract: 4times16 arrays of micro-pixellated InGaN LEDs, each of diameter 72 mum, have been flip-chipped onto CMOS driver backplanes which also contain single-photon avalanche photodiodes. Pattern-programmable control is demonstrated in continuous and nanosecond modes. Such devices show promise as miniaturized excitation and detection systems for microfluorimetry studies.

Integration of IC technology with MEMS: Silicon+ technology for the future

Abstract: As silicon integrated circuits (ICs) continue their development scaling to smaller geometries there are increasing signs that the industry is diversifying into new device types and associated new application areas. The mainstream IC industry which is manufacturing devices such as memories and microprocessors will be following the ITRS roadmap towards smaller and smaller devices. However, in parallel, there will be an increasing activity involving the integration of silicon with other technologies and new materials, and it is clear that MEMS will form an important component of this Silicon+ activity. This paper identifies the options available for integrating MEMS with IC technology and examples will be used to identify the issues associated with their implementation through a number of examples.

A Buried Triple-Junction Self-Reset Pixel in a 0.35µm High Voltage CMOS Process

Abstract: Light to frequency converters are used to sense the photocurrents of a buried triplejunction pixel achieving high dynamic range and low dark current colour sensing without the use of colour filters. The pixel is realised in a high voltage 0.35μm CMOS enabling sample manipulation by electrowetting and spectral sensing for a FRET biosensor.