Kouichi Masubuchi

Influence of Fermi‐level pinning on barrier height inhomogeneity in PtSi/p‐Si Schottky contacts

The barrier height inhomogeneity in PtSi/p‐Si and IrSi/p‐Si was observed by internal photoemission. New Fowler equations were introduced, to analyze the observed properties. Two regions with different barrier heights were assumed to coexist, and the individual barrier heights were evaluated. One of two barrier heights was consistent with the generally obtained value in individual contacts. The other was 0.39 eV in both contacts. The origin of two regions was explained in terms of Fermi‐level pinning.

A standard-television compatible 648*487 pixel Schottky-barrier infrared CCD image sensor

Describes a 648*487 pixel PtSi Schottky-barrier infrared CCD image sensor. Due to the development of the modified inverted-LOCOS process, which can minimize dead regions, and the two-dopant concentration structure, which achieves both a large charge capability and high transfer efficiency, a 40% fill factor in a 21- mu m*21- mu m pixel and a 0.1-K noise equivalent temperature difference were obtained. >

324*487 Schottky-barrier infrared imager

A standard TV-compatible PtSi Schottky-barrier infrared imager is described. The imager is a 324*487 element area array and has an electronic shutter function. Although the pixel is 42*21 mu m, a large fill factor of 42% is obtained, using a 1.5- mu m minimum design rule and a two-level polysilicon layer, and two-level aluminum layer structure. Using face-down bonding technology, it was possible to reduce the package size to 60% of the conventional ceramic package size. Due to optimization of the Schottky-barrier diode process and the diode structure, the noise equivalent temperature difference is as small as 0.1 K at f/1. >

An infrared-bi-color Schottky-barrier CCD image sensor for precise thermal images

An infrared-bi-color image sensor was developed with a barrier height controlled Schottky-barrier photo diode array for precise temperature images. Low and high barrier height diode pixels are arranged vertically next to one another using a selective area ion implantation technique. Conventional monochrome infrared image sensors frequently give wrong temperature images due to an unreasonable emissivity assumption. The infrared-bi-color image sensor can obtain the temperature image precisely with regard to the emissivity of the object.

High fill factor and progressive scan PtSi Schottky-barrier IR-CCD image sensor having new wiring structure over photodiodes

A back surface illuminated 130/spl times/130 pixel PtSi Schottky-barrier (SB) IR-CCD image sensor has been developed by using a new wiring structure, referred to as CLOSE Wiring. CLOSE Wiring, designed to effectively utilize the space over the SB photodiodes, brings about flexibility in clock line designing, high fill factor, and large charge handling capability in a vertical CCD (VCCD). This image sensor uses a progressive scanned interline-scheme, and has a 64.4 percent fill factor and 3.3 /spl mu/m wide VCCD in a 30 /spl mu/m/spl square/ pixel. The charge handling capability for VCCD achieves 9.8/spl times/10/sup 5/ electrons. The noise equivalent temperature difference obtained was 0.099 K for operation at 120 frames/sec with f/1.3 optics.<<ETX>>

Utilizing an optical cavity to increase the saturation level in a Schottky-barrier IR image sensor

A precise evaluation of the photodiode storage capacitance in a platinum silicide Schottky- barrier IR image sensor with an optical cavity and in which an aluminum reflector is electrically grounded has revealed that the cavity capacitance between the aluminum reflector and the platinum silicide film, which is one of four components in the photodiode storage capacitance, is dominant. While this area of the photodiode has previously been investigated for its optical characteristics, the present study represents the first reported investigation on its electrical characteristics. In order to increase the saturation level of an image sensor, it is essential to increase the storage capacitance in its photodiode. The storage capacitance in the photodiode was shown to be increased not only by newly using but also by increasing the cavity capacitance. When the SiO2 film between the aluminum reflector and the platinum silicide film was replaced with SiN, total storage capacitance in the photodiode was successfully increased by a factor of 1.6, while the optical characteristics of the photodiode remained the same.

A high fill factor and progressive scan PtSi Schottky-barrier IR-CCD image sensor using new wiring technology

A back surface illuminated 130/spl times/130 pixel PtSi Schottky-barrier (SB) IR-CCD image sensor has been developed by using new wiring technology, referred to as CLOSE Wiring, CLOSE Wiring, designed to effectively utilize the space over the SB photodiodes, brings about flexibility in clock line designing, high fill factor, and large charge handling capability in a vertical CCD (VCCD). This image sensor uses a progressive scanned interline-scheme, and has a 64.4% fill factor in a 30 /spl mu/m/spl times/30 /spl mu/m pixel, a 3.9 mm/spl times/3.9 mm image area, and a 5.5 mm/spl times/5.5 mm chip size. The charge handling capability for the 3.3 /spl mu/m wide VCCD achieves 9.8/spl times/10/sup 5/ electrons, The noise equivalent temperature difference obtained was 0.099 K for operation at 120 frames/sec with a 50 mm f/1.3 lens. >

An infrared-bi-color Schottky-barrier infrared CCD image sensor for precise thermal image

An infrared-bi-color image sensor was developed with barrier height controlled Schottky-barrier photo diode array for precise temperature image. Vertically arranged low and high barrier height diode pixels in horizontally stripe order were arranged by using a selective area ion implantation technique. Conventional monochromatic infrared image sensors have only measured the temperature for a black body object. The infrared-bi-color image sensor can precisely obtain the temperature image for gray bodies, whose emissivity values are unknown.<<ETX>>

Solid State Imaging Techniques. An Infrared-Bi-Color Image Sensor for Precise Thermal Images.

An infrared-bi-color image sensor was developed with a barrier-height-controlled Schottky-barrier photo diode array for precise temperature images. Low and high barrier-height diode pixels are arranged vertically next to one another using a selective area ion-implantation technique. The infrared-bi-color image sensor can obtain the temperature image precisely and without the emissivity assumption.

Optimum barrier height in Schottky-barrier infrared CCD image sensor

Noise equivalent temperature difference (NE(Delta) T) values in a PtSi Schottky-barrier (SB) infrared CCD image sensor are calculated with variations in spectral response, device operating temperature, and internal radiation intensity generated from a lens barrel, using measured values from a recently developed 648 X 487 pixel SB infrared CCD image sensor. The barrier height is allowed to vary, whereas it was fixed before. NE(Delta) T values were calculated as a function of barrier height and were found to have a minimum. The optimum barrier height depends on quantum efficiency coefficient, device operating temperature, and internal radiation intensity.