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A 1.2-Mpixel indirect time-of-flight (ToF) CMOS image sensor is presented to lower peak current and to cancel out multi-user interference. The proposed 4-tap 3.5- $\mu \text{m}$ demodulation pixel is optimally designed to improve quantum efficiency (QE) and demodulation contrast (DC). A new “multiple-interleaving” scheme is proposed to reduce the peak current and self-compensate fixed-pattern phase noise (FPPN) with the minimal side effect of DC imbalance. To cancel out interference from the other ToF sensors, a multi-user interference cancellation (MUIC) scheme based on pseudorandom modulation is adopted. From the measurement results, we achieve a high QE of 38% at 940 nm and a high DC of 96% and 80% at 100- and 200-MHz modulation frequencies, respectively. With the superior pixel performance, the depth noise of $\times $ 2 binning modes, respectively. The multiple-interleaving scheme suppresses the peak current to less than 0.9 A and removes the column FPPN with constant DC for the whole pixel array. The proposed MUIC proves that at least two interferers can be successfully rejected. The sensor chip is fabricated in a two-stack process with 65 nm for the top die and 65 nm for the bottom die.

The evolution of 3D depth-sensing technology enables various applications in mobile devices, from conventional photography enhancement (e.g., autofocus and bokeh effect) to new applications such as augmented reality and 3D scanning. Usually, 3D depth sensors operate with RGB color sensors for image fusion; the spatial resolution of depth sensors should be compatible to that of RGB sensors for better image fusion quality, which requires mega-pixel depth sensors. Among different depth-sensing techniques, only indirect time-of-flight (ToF) sensors can generate higher resolution depth maps with smaller system cost and power [1,2]. Recent indirect ToF sensors have achieved continuous improvements in depth performance [1–4]. However, one of the issues with indirect ToF sensors is peak current during exposure time [1,2]. To solve the issue, current spreading can be adopted by driving each column group in a different time point; the resulting column fixed-pattern phase noise (FPPN) is compensated by time-interleaving two opposite-directional delay chains [2]. However, this approach suffers from demodulation contrast (DC) degradation around the edge of the pixel array, by combining two different phase signals at the pixel level [2]. Another issue for indirect ToF sensors is multi-user interference [5]. When multiple ToF cameras with the same modulation frequency shine light onto the same object, the reflected light signals interfere each other, which may distort depth information. In this work, a mega-pixel indirect ToF sensor is reported with the solutions for the two issues: 1) peak current mitigation with minimal side-effect, and 2) multi-user interference cancellation.

A 2.8μm 4-tap global shutter pixel has been realized for a compact and high-resolution time of flight (ToF) CMOS image sensor. 20,000 e- of high full-well capacity (FWC) per a tap is obtained by employing a supplementary MOS capacitor. 36% of high quantum efficiency (QE) has been achieved by backside scattering technology (BST) and thick silicon process. In addition, demodulation contrast (DC) is improved to 86 % by additional deep photodiode doping process for static potential gradient in a photodiode.

A 0.8μm-pitch 108 megapixels (Mp) ultrahigh-resolution CMOS image sensor has been demonstrated for mobile applications. The Nonacell was developed through a 3x3 color filter and 1x3 shared pixel structures which can be operated the 3 binning mode to achieve 12Mp resolution and improve low-illuminance signal-to-noise ratio (SNR) characteristic. The full-well capacity (FWC) of Nonacell was achieved up to 18,000e- using FD-shared dual conversion gain (CG) technology, and excellent high-illuminance SNR was demonstrated.

As the smart mobile device market continues to grow and the number of cameras per device rapidly increases, demand for CMOS image sensors (CIS) also increases. Two major trends in mobile device cameras are: (1) adopting smaller pixels that enable greater pixel count at similar optical format, and (2) bigger pixels for higher image quality. To be more specific, front-facing cameras have a trend towards smaller pixels, while rear main cameras have a trend towards both smaller and bigger pixels. The optical format of front-facing cameras is especially limited due to existing bezel-less or border-less display designs, yet higher resolution still-shot and video (such as 4K UHD) recording is desired. To implement greater pixel count in a limited camera module size, scaling of pixel size is required. The main challenges are to maintain acceptable photodiode full-well capacity (FWC) and sensitivity, while suppressing optical crosstalk [1]. To completely eliminate both electrical and optical crosstalk, deep-trench isolation (DTI) has evolved from early BDTI (Back-side DTI) to current FDTI (Front-side DTI) technology, which is also called full-depth DTI. In this paper, a 44Mpixel CIS with 0.7µm pixels using full-depth DTI is demonstrated.

Genomes are mostly protected from constant DNA-damaging threats, either internal or external, which ultimately sustain the organism. Herein, we report that AIMP3, a previously demonstrated tumour suppressor, plays an essential role in maintaining genome integrity in adult mice. Upon induction of the temporal systemic deletion of AIMP3 by tamoxifen in adult mice, the animals developed an acute radiation syndrome-like phenotype, typified by scleroderma, hypotrophy of haematopoietic cells and organs, and intestinal failure. Induction of γH2AX, an early marker of DNA double-strand breaks, was observed in the spleen, intestine, and the highly replicating embryonic cortex. In addition, sub-lethal irradiation of AIMP3 mKO mice dramatically affected organ damage and survival. Using isolated MEFs from conditional KO mice or AIMP3 knockdown cells, we confirmed the presence of spontaneously occurring DNA double-strand breaks by COMET assay and γH2AX induction. Furthermore, γH2AX removal was delayed, and homologous DNA repair activity was significantly reduced. Reduction of RPA foci formation and subsequent Rad51 foci formation probably underlie the significant reduction in homologous recombination activity in the absence of AIMP3. Together, our data demonstrate that AIMP3 plays a role in genome stability through the DNA repair process.

CMOS image sensors (CIS) have attracted much attention for the emerging mobile market, and the demand of high-resolution image sensors in mobile applications continues to increase [1-3]. For this reason, pixel pitch has been reduced down to 1.0μσι for mass production. Nevertheless, CISs are continuously scaling down to meet the strong demand for higher-resolution images. However, when the pixel size is reduced down to the sub-micron regime (possibly smaller than the diffraction limit), it is very important to consider photo sensitivity and crosstalk, which determine signal-to-noise ratio (SNR). To minimize degradation of photo sensitivity, back-side illumination (BSI), which collects light at the back side, is widely used instead of front-side illumination. In addition to BSI technology, deep-trench isolation (DTI) has emerged as a leading candidate to suppress crosstalk since it physically isolates the pixel. Previous work shows that partial-depth DTI can be applied in a 1.12μm-pitch pixel [4]. Furthermore, full-depth DTI has been demonstrated in a 1.12μm pixel with 24% larger full-well capacity (FWC), 30% smaller YSNR10, 2.0dB higher SNR, and especially for lower crosstalk (12.5%) compared with a conventional one [5]. In this work, a 24-Mpixel CIS with 0.9μσι unit pixels that takes advantage of full-depth DTI is demonstrated.

With advanced design rules, yield learning challenges have scaled up. Identifying and analyzing yield killer defects are one of the major part of the issue. In this work, an advanced Inspection platform - '2810 DUV Broadband Brightfield' Inspection tool and Stack CV® (Characterization Vehicle®) test chips developed by PDF Solutions are used to identify systematic as well as random defects causing yield drop, and monitor key DOI (Defects-of-Interest) for accelerated defect-based yield learning at the 45nm technology node. 2810 DUV Broadband illumination, in-line defect organizer [iDO] & RICO [Review inspector cycle optimization] of eDR SEM review tool were key features employed during inspection recipe optimization. Stack CV® test chips contained diverse pattern lay-outs which provide platform for characterization of yield limiting factors. Using this methodology, 'E-test - In-line defect detection correlation' was matched to target benchmark capture rate values for FEOL and BEOL at Samsung S-1, a leading 300mm fab. Learnings derived from this study have enabled faster yield ramp-up on production devices.

According to the trend towards high-resolution CMOS image sensors, pixel sizes are continuously shrinking, towards and below 1.0μm, and sizes are now reaching a technological limit to meet required SNR performance [1-2]. SNR at low-light conditions, which is a key performance metric, is determined by the sensitivity and crosstalk in pixels. To improve sensitivity, pixel technology has migrated from frontside illumination (FSI) to backside illumiation (BSI) as pixel size shrinks down. In BSI technology, it is very difficult to further increase the sensitivity in a pixel of near-1.0μm size because there are no structural obstacles for incident light from micro-lens to photodiode. Therefore the only way to improve low-light SNR is to reduce crosstalk, which makes the non-diagonal elements of the color-correction matrix (CCM) close to zero and thus reduces color noise [3]. The best way to improve crosstalk is to introduce a complete physical isolation between neighboring pixels, e.g., using deep-trench isolation (DTI). So far, a few attempts using DTI have been made to suppress silicon crosstalk. A backside DTI in as small as 1.12μm-pixel, which is formed in the BSI process, is reported in [4], but it is just an intermediate step in the DTI-related technology because it cannot completely prevent silicon crosstalk, especially for long wavelengths of light. On the other hand, front-side DTIs for FSI pixels [5] and BSI pixels [6] are reported. In [5], however, DTI is present not only along the periphery of each pixel, but also invades into the pixel so that it is inefficient in terms of gathering incident light and providing sufficient amount of photodiode area. In [6], the pixel size is as large as 2.0μm and it is hard to scale down with this technology for near 1.0μm pitch because DTI width imposes a critical limit on the sufficient amount of photodiode area for full-well capacity. Thus, a new technological advance is necessary to realize the ideal front DTI in a small size pixel near 1.0μm.

We report a spectrum-sliced amplified spontaneous emission-injected wide-band gain laser covering a temperature range over 110/spl deg/C as well as entire 32 100-GHz-spaced channels (1533-1558 nm) in 155-Mb/s upstream transmissions over 25 km of single-mode fiber in a wavelength-division-multiplexed passive optical network. The wide-band gain laser diode employs asymmetric multiple quantum-well structure and low antireflection coating in order to widen the gain spectrum.

A 1.25-Gb/s burst-mode receiver for the application of 32 splits and 20-km transmission in Ethernet-based passive optical network was developed using a general planar type avalanche breakdown photodiode and a low-cost continuous-mode transimpedance amplifier (TIA). The largest loud/soft ratio (27.3 dB) and high sensitivity (-33.3 dBm) were achieved in 896-ns guard band. The minimum automatic gain control (AGC) time of the TIA was obtained without using a high value external AGC capacitor that is needed for the stable continuous operation. The guard time could be minimized while maintaining the burst performances due to the fast laser on-off time of the optical network units.

Using the W damascene process in the pixel area, M1Top pixel structure was developed. Because the M1Top pixel structure does not use the metal2 layer in the pixel block, total stack height becomes much thinner than normal pixels. From this new structure, sensitivity and QE in 1.75um pixels have been improved by 50% from that of normal M2Top pixels in 0.11um CIS process.

A WDM-PON with 50-GHz channel spacing employing RSOA-based spectrum sliced sources is presented. Colorless operations over 32 DWDM channels are demonstrated from -10 to 80 °C in 155-Mb/s transmissions over 10 km.

Uncooled ASE-injected WBG-LDs in the S-band are first developed as downstream sources in WDM-PONs. The single WBG-LD covers 100 GHz-spaced 32 channels and allows BERs of 10-10 with +2 dBm launching power over 25 km

We report a spectrum-sliced amplified spontaneous emission (ASE)-injected wideband gain laser covering entire C-hand wavelength channels with temperature range from -30 to 80 /spl deg/C in 155 Mb/s upstream transmissions over 25 km of single mode fiber in a wavelength division multiplexed-passive optical networks (WDM-PON).