• 센서학회지
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• 제15권5호
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• pp.341-346
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• 2006

We have fabricated SOI CMOS active pixel image sensor with the pinned photodiode on handle wafer in order to reduce dark currents and improve spectral response. The structure of the active pixel image sensor is 4 transistors APS which consists of a reset and source follower transistor on seed wafer, and is comprised of the photodiode, transfer gate, and floating diffusion on handle wafer. The source of dark current caused by the interface traps located on the surface of a photodiode is able to be eliminated, as we apply the pinned photodiode. The source of dark currents between shallow trench isolation and the depletion region of a photodiode can be also eliminated by the planner process of the hybrid bulk/SOI structure. The photodiode could be optimized for better spectral response because the process of a photodiode on handle wafer is independent of that of transistors on seed wafer. The dark current was about 6 pA at 3.3 V of floating diffusion voltage in the case of transfer gate TX = 0 V and TX=3.3 V, respectively. The spectral response of the pinned photodiode was observed flat in the wavelength range from green to red.

• 반도체디스플레이기술학회지
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• 제16권2호
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• pp.15-18
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• 2017

In this study, we have studied the characteristics of the organic photodiode varying due to the blending conditions of the quantum dots (QDs). The active layer of the photodiode was formed with poly (3-hexylthiophene) and phenyl-C61-butyric acid methyl ester, and CdSe QDs with and without ZnS shell were blended in the active layer. The photodiode with CdSe/ZnS QDs showed the highest power conversion efficiency (PCE) and short-circuit current (Jsc). The performance change of the organic photodiode by X-ray irradiation was also measured. Regardless of X-ray irradiation conditions, the photodiode with CdSe/ZnS QDs showed better stability than other cases.

• 대한방사선기술학회지:방사선기술과학
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• 제19권2호
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• pp.71-77
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• 1996

Studies were conducted to determine the clinical application of photodiode. We compared photodiode with ion-chamber as to change of tube potential, tube current, mAs and measured decreasing rate of penetration dose. When tube potential was changed from 60 kVp to 120 kVp, output of photodiode and ion-chamber were changed from 0.4 to 1.625, and 1.018 to 4.268, respectively. This was a good agreement to theory that $I=Kv^2it$(I is intensity, K is constant, v is tube potential, i is tube current, t is time). Characteristics for change of tube current and mAs were also a good agreement to theory. And comparison in decreasing rate of penetration dose was similar except above 6 cm in depth. Our results indicated that photodiode was a good instrument for relative measurement of radiation exposure, but we can not use the photodiode for absolute radiation dose.

• 한국전기전자재료학회논문지
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• 제21권9호
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• pp.863-867
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• 2008

In this paper, to increase the light current efficiency of photodiode, we fabricated aluminum-doped zinc oxide(AZO) thin films by RF magnetron sputtering. AZO thin films were deposited at low temperature of 100 $^{\circ}C$ and different RF powers of 50, 100, 150 and 200 W due to selective process technology. Then the AZO thin films were annealed at 400 $^{\circ}C$ for 1 hr in vacuum ambient to increase crystalline. The lowest resistivity of 1.35 ${\times}$ $10^{-3}$ ${\Omega}cm$ and a high transmittance over 90 % were obtained under the conditions of 3 mTorr, 100 'c and 150 W. The optimized AZO thin films were deposited as anti-reflection coating on PN junction of silicon photodiode. It was confirmed by the result of $V_r-I_{ph}$ curve that the efficiency of photodiode with AZO thin film was enhanced 17 % more than commercial photodiode.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1340-1343
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• 2007

We have simultaneously fabricated LTPS TFTs and integrated photodiodes on the same glass substrates without any additional LTPS process. The structure of an integrated photodiode is a lateral p-i-n diode with a gate. The performances of a photodiode were improved at a negative gate voltage.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 하계학술발표회
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• pp.98-99
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• 2003

PIN photodiode has been used in solid-state detector for x-ray detection as a photosensor of visible light from scintillator. Since the light from CWO is short wavelength having peak at 490nm, the light is absorbed within a very shallow layer near the surface of the photodiode before arriving at the depletion layer and does not contribute to the signal. In designing the PIN photodiode, it is important to make the p-layer as shallow as possible. (omitted)

• 한국정보통신학회논문지
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• 제10권1호
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• pp.111-116
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• 2006

본 연구에서는 비정질 실리콘 박막 트랜지스터를 스위칭소자로 포토센서를 구동 하는 방식의 이미지 센서를 구현하고자 한다. 먼저 PECVD(Plasma Enhanced Chemical Vapor Deposition) 진공 증착장비로 최적의 비정질실리콘 박막을 형성하고, 이 박막을 이용하여 스위칭소자인 박막트랜지스터와 광전변환소자인 광다이오드를 제조한다. 또한 이들을 결합하여 이미지 센서를 형성하고 그 특성 및 동작을 분석하고 최적의 동작특성을 이끌 수 있는 밀착이미지 센서를 제조한다. 제작한 이미지 센서를 측정한 결과 광전변환소자인 photodiode는 암전류의 경우 $\~10^{-l2}A$정도였으며, 광전류 $\~10^{-9}A$정도로서 Iphoto/Idark ${\ge}10^3$ 이상을 이루어 좋은 광전변환 특성을 갖고 있었다. 또한 a-Si:H TFT의 경우 Ioff ${\le}10^{-l2}A$, Ion ${\le}10^{-6}A$ 으로서 Ion/Ioff ${le}10^6$ 이상을 나타냈으며 Vth는 $2\~4$ volts였고, Id는 수 ${\mu}A$ 정도로 photodiode를 스위치하기에 충분한 전류-전압특성을 나타내고 있다. 이미지 센서 전체 동작 특성을 측정하기 위하여 photodiode의 ITO쪽에 -5volts의 역 bias를 가한 상태에서 TFT의 gate에 $70\;{\mu}sec$의 pulse를 가하여 photodiode에서 생성된 광전류 와 암전류를 측정하였다. 이렇게 하여 측정된 전압은 암상태에서 수십 mvolts이고, 광상태에서는 수백 mvolts로 나타나 우수한 이미지센서 특성을 갖고 있음을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제14권2호
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• pp.211-215
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• 1993

A multichannel optical detector system employing a self-scanning linear photodiode array has been developed. The photodiode array detector system is designed for various applications which require fast, multichannel detection of transient signals. The detector system consists of a controller which runs on an IBM personal computer and a detector head connected to the controller through a DB-15 cable. The entire scanning of 1024 detector elements is achieved in 20 ms. By using an on-board 16-bit counter/timer, the operational mode of the photodiode array detector is fully programmable by software. The design considerations and the performance of the photodiode array detector system is presented.

• 한국정밀공학회지
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• 제12권10호
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• pp.69-77
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• 1995

This laser measurement system has been developed using He-Ne laser and photodiode. The laser beam intensity transmitted on a photodiode was disturbed by eccentrically rotating disk cam with various speeds. The photodiode and an amplifier were used to change the detected beam intensity into voltage. The digitized data through the developed system were recorded on a micro-computer by using a signal analysis program. Its reliability was ascertained by using FFT analyzer. The vibration of rotating disk cam can be analyzed by measureing the intensity change of laser beam which the results by FFT analyzer were similar to. The amplifier was devised to be able to modulate the fluctuations of laser beam. The voltage could be linearly recorded with the change of the laser beam intensity.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.482-485
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• 2004

We fabricated a hybrid bulk/fully depleted silicon on insulator (FDSOI) complementary metal oxide semiconductor (CMOS) active pixel image sensor. The active pixel is comprised of reset and source follower transistors on the SOI seed wafer, while the pinned photodiode and readout gate and floating diffusion are fabricated on the SOI handle wafer after the removal of the buried oxide. The source of dark current is eliminated by hybrid bulk/FDSOI pixel structure between localized oxidation of silicon (LOCOS) and photodiode(PD). By using the low noise hybrid pixel structure, dark currents qm be suppressed significantly. The pinned photodiode can also be optimized for quantum efficiency and reduce the noise of dark current. The spectral response of the pinned photodiode on the SOI handle wafer is very flat between 400 nm and 700 nm and the dark current that is higher than desired is about 10 nA/cm2 at a $V_{DD}$ of 2 V.