Session 24: Displays, Sensors, and MEMS - Imagers and Integrated Sensors

Wednesday, December 12, 9:00 a.m.
Continental Ballroom 1-3

Co-Chairs: Edoardo Charbon, Technical University Delft
Pierre Magnan, SAE

9:00 a.m.
Introduction

9:05 a.m.
24.1  Evolution of Optical Structure in Image Sensors (Invited), N. Teranishi, H. Watanabe, T. Ueda, N. Sengoku, Panasonic Corporation

Monolithic optical structures for light gathering in image sensors are focused. First, microlens progresses, such as gapless microlens, inner microlens and light pipe are explained. Then, back side illumination (BSI) is compared with front side illumination (FSI). Lastly, recent FSI technology, SmartFSITM, is reported along with its pixel shrinkage results.

9:30 a.m.
24.2  Suppression of Crosstalk by Using Backside Deep Trench Isolation for 1.12µm Backside Illuminated CMOS Image Sensor, Y. Kitamura, H. Aikawa, K. Kakehi, T. Yosho, K. Eda, T. Minami, S. Uya, Y. Takegawa, H. Yamashita, Y. Kohyama, T. Asami, Toshiba Corporation

1.12um backside illuminated CMOS image sensor with backside deep trench isolation (DTI) has been demonstrated for the first time. DTI is fabricated on backside surface after wafer bonding and grinding process. Backside DTI makes its layout simple because no transistor isolation exists on backside. We have confirmed 50% reduction of crosstalk.

9:55 a.m.
24.3  How to Achieve Ultra High Photoconductive Gain for Transparent Oxide Semiconductor Image Sensors, S. Lee, A. Nathan*, J. Robertson*, University College London, *Cambridge University

This work presents a complete and quantitative analysis of the ultra-high extrinsic quantum efficiency in amorphous oxide hetero-TFT image sensors, taking into account the high sub-gap optical absorption due to oxygen vacancies, extended electron lifetime due to retarded recombination, and the reduced transit time associated with short channel lengths.

10:20 a.m.
24.4  InGaAs/InP SPAD with Improved Structure for Sharp Timing Response, A. Tosi, F. Acerbi, M. Anti, F. Zappa, Politecnico di Milano

We designed and fabricated an In_0.53Ga_0.47As/InP Single-Photon Avalanche Diode with improved layer structure and diffusion geometry in order to achieve good detection efficiency (30% at 1550 nm), low afterpulsing (gate repetition frequency > 1 MHz) and good timing performance (timing response has 57 ps FWHM and 30 ps tail).

10:45 a.m.
24.5  High Photocurrent and Quantum Efficiency of Graphene Stack Photodetector Assembled by Layer-by-Layer Transfer, H.-M. Li, T.-Z. Shen, D.-Y. Lee, W. J. Yoo, Sungkyunkwan University

A graphene stack (GS) structure assembled by layer-by-layer (LBL) transfer of single-layer graphene (SLG) is applied in field effect transistors (FETs) for photodetection. Excellent optoelectronic performance of ~3.6 times increased photocurrent (PC) together with increased internal/external quantum efficiency (IQE/EQE) is obtained in the LBL-GS-FET compared to the conventional SLG-FET, owing to (i) the improved electrical transport, e.g., carrier mobility (4.1 times higher), sheet resistance (61% reduced) and contact resistance (81% reduced) etc., and (ii) the increased optical absorption (over fivefold higher in the visible spectrum). A photovoltaic (PV) model of the LBL-GS-FET was established, indicating a peak of PC generation due to the optimized gate modulation. Both the experimental and theoretical results suggest the LBL-GS as an excellent material for high efficiency optoelectronics.

11:10 a.m.
24.6  A CMOS-MEMS-Based Label-Free Protein Sensor for High-Sensitive and Compact System, K. Takahashi, R. Ozawa, H. Oyama, M. Futagawa, F. Dasai, M. Ishida, K. Sawada, Toyohashi University of Technology

We have developed a CMOS-MEMS-based label-free protein sensor, which utilizes nonlinear optical transmittance change by the Fabry-Perot interference to enhance the sensitivity of surface-stress. A read-out tiny photocurrent from the multidimensional arrayed MEMS sensor is signal-processed by integrated source follower circuit, selector, and decoder. The integrated MEMS sensor array can be used for screening analysis for any cancers.

11:35 a.m.
24.7  Exceeding Nernst Limit (59mV/pH): CMOS-Based pH Sensor for Autonomous Applications, K. Parizi, J. Yeh, A. Poon, H.-S.P. Wong, Stanford University

A highly sensitive and accurate field-effect sensor was obtained in a standard differential pair CMOS structure without Ag/AgCl reference electrode. The device is composed of two sensors each with a ?oating gate (FG) field effect transistor (FET), a control gate (CG) and an extended sensing gate (SG). By extending the sensing gate and engineering the capacitance value of the CG, we achieved a remarkable sensitivity of 130mV/pH for our pH sensor exceeding the fundamental Nernst limit, 59mV/pH. In addition, we removed the bulky Ag/AgCl reference electrode by a novel technique employing differential measurement to cancel the effect of the common abnormal potential change occurs in the solution.