C. Y. Lin

Light guide for pixel crosstalk improvement in deep submicron CMOS image sensor

Light guide, a novel dielectric structure consisting of PE-Oxide and FSG-Oxide, has been developed to reduce crosstalk in 0.18-/spl mu/m CMOS image sensor technology. Due to the difference in refraction index (1.46 for PE-Oxide and 1.435 for FSG-Oxide), major part of the incident light can be totally reflected at the interface of PE-Oxide/FSG-Oxide, as the incidence angle is larger than total reflection angle. With this light guide, the pixel sensing capability can be enhanced and to reduce pixel crosstalk. Small pixels with pitch 3.0-/spl mu/m and 4.0-/spl mu/m have been characterized and examined. In 3.0-/spl mu/m pixel, optical crosstalk achieves 30% reduction for incidence angle of light at 10/spl deg/.

Trench Pd/Si metal‐oxide‐semiconductor Schottky barrier diode for a high sensitivity hydrogen gas sensor

The structure and hydrogen gas sensing properties of a trench Pd‐thin oxide‐Si Schottky diode are studied and compared with a planar one. The trench diode possesses additional vertical surface area and a large number of interface traps induced by injected hydrogen ions. The additional vertical surface area enlarges the entrance of H2 molecules, and the generated middle traps enhance the carrier tunneling. Also, the generated shallow traps can catch the carrier to form a thin surface charge layer and lower the barrier. The sensitivity of the trench diode is thus higher than that of the planar diode under room‐temperature operation.

A deep submicrometer CMOS process compatible high-Q air-gap solenoid inductor with laterally laid structure

A high-quality (Q) on-chip solenoid inductor has been fabricated by 0.18 mm CMOS technology with air-gap structure. The solenoid structure with laterally laid out structure saves the chip area significantly and the air-gap suppresses the parasitic capacitances to obtain high-Q value. Additionally, with software ANSYS simulation, the solenoid inductor also possesses a higher strength for impact (80 000 times) in comparison to a spiral inductor. The measured peak-Q and peak-Q frequency with an air-gap are 8.8 and 1.7 GHz, respectively, which present almost 9% improvements in the magnitude and 54% in the peak-Q frequency in comparison to the conventional solenoid inductor at 8.1 and 1.1 GHz.

Dramatic reduction of optical crosstalk in deep-submicrometer CMOS imager with air gap guard ring

A dielectric structure, air gap guard ring, has been successfully developed to reduce optical crosstalk thus improving pixel sensitivity of CMOS image sensor with 0.18-/spl mu/m technology. Based on refraction index (RI) differences between dielectric films (RI = 1.4 /spl sim/ 1.6) and air gap (RI = 1), total internal reflection occurred at dielectric-film/air-gap interface, thus the incident light is concentrated in selected pixel. Excellent optical performances have been demonstrated in 3.0 /spl times/ 3.0 /spl mu/m pixel. Optical spatial crosstalk achieves 80% reduction at 20/spl deg/ incidence angle and significantly alleviates the pixel sensitivity degradation with larger angle of incident light.

Color mixing improvement of CMOS image sensor with air-gap-guard ring in deep-submicrometer CMOS technology

In this letter, color mixings of a CMOS image sensor with air-gap-guard-ring (AGGR) and conventional structures were investigated in 0.18-/spl mu/m CMOS image sensor technology. As the light incident angle is increased from 0/spl deg/ to 15/spl deg/, conventional pixel shows serious color mixing. For example, the maximum photo responses of blue, green1, green2, and red pixels are shifted from 490 to 520 nm, 530 to 500 nm, 530 to 600 nm, and 600 to 580 nm, respectively. However, pixels with AGGR not only keep correct spectral response without peak shift but also achieve 5%-50% crosstalk reduction, thus preventing the sensor from color mixing efficiently.

Dramatic improving luminous efficiency of organic light emitting diodes under low driving current using nitrogen doped hole transporter

Abstract In this letter, output luminance, current efficiency and power efficiency of the organic light emitting diodes (OLEDs) with N 2 doped hole transport layer (HTL) have been studied in detail. Experimental results show that the current efficiency and the power efficiency thus in turn the output luminance of OLEDs prepared with HTL evaporated in the optimum N 2 gas ambient pressure of 1×10 −4 Torr are improved about 13, 9 and 12 times, respectively, under 2.7 mA/cm 2 driving current. The significant improving mechanism has been illustrated comprehensively with a series of schematic models.

Improving turn on voltage and driving voltage of organic electroluminescent devices with nitrogen doped electron transporter

Abstract In this letter, I/V curves, output luminance of the organic light emitting diodes (OLEDs) with N2 doped electron transport layer (ETL) have been studied in detail. Experimental results show that the turn on voltage and driving voltage of OLEDs with ETL evaporated in the optimum N2 gas ambient pressure of 1×10−4 Torr are reduced from 3.5 to 1 V and 7.7 to 5.7 V, respectively. The significant improving mechanism has been illustrated comprehensively with a schematic energy diagram model.

An effective method to improve the sensitivity of deep submicrometer CMOS image sensors

An effective method has been successfully developed to improve the sensitivity of deep sub-micrometer CMOS image sensors (CIS). In advanced CIS technology, the shallow trench isolation (STI) SiO/sub 2/ on the photodiode and the SiON film are used for silicide blocking and as a contact etching-stop layer, respectively. However, the dielectric structure, which is composed of an interlayer dielectric/SiON/STI/spl I.bar/SiO/sub 2//Si, causes a destructive interference and thus degrades quantum efficiency (QE), especially at short wavelengths. In this paper, an effective method for improving CIS sensitivity has been proposed, based on both theoretical analysis and simulation results, by removing the STI from the photodiode area and then forming a deposition of SiON. Experimental results show that a 40% QE improvement can be achieved under the irradiance of light at a wavelength of 450 nm.

Failure Mechanism of Electromigration in Via Sidewall for Copper Dual Damascene Interconnection

We have studied the effects of step coverage of TaN diffusion barrier layer on Cu electromigration (EM) in detail and found that the EM lifetime strongly depends on the step coverage of via sidewall thickness. We conclude that the EM failures are caused by mechanisms such as unbalanced thermal stress, thermal expansion between Cu and TaN, and surface morphology of TaN including surface roughness and grain sizes. These factors were investigated and evaluated systematically through transmission electron microscopy, field emission scanning electron microscopy, and atomic force microscopy. Furthermore, we also address the enhancement of step coverage to examine Cu EM performance by performing a lifetime experiment, and suggest that the step coverage of TaN barrier becomes an important process integration subject for sub-0.13 μm and beyond technologies.

The mechanism and evaluation of hot-carrier-induced performance degradation in 0.18-/spl mu/m CMOS image sensor

An effective method to evaluate the hot-carrier-induced pixel performance degradation of 0.18-/spl mu/m CMOS active pixel sensor has been reported. The hot carriers generated at the source follower transistor and absorbed by the nearby photodiode will cause the pixel performance degradation such as increase of dark signal and decrease of operation range. Based on the detailed measurements through overall operation conditions, a simple method has been proposed to evaluate the degradation induced by the hot carriers and, thus, provides a design guide to predict pixel performance.