Kazuo Konuma

Carbon-nanotube-based triode-field-emission displays using gated emitter structure

We fabricated a carbon-nanotube-based triode-field-emission display with a gated emitter structure made up of a gate layer, a thin insulating layer, and a carbon nanotube layer. A low threshold voltage of 20 V and a total anode current of 0.5 mA at 80 V were observed for 30/spl times/30 pixel panels. We also demonstrated highly efficient and homogeneous emission from all pixels at voltages lower than 100 V. Based on simulation of electric fields in gate holes, further improvement of the emission properties is expected by optimizing its structural parameters, such as the gate-hole diameter.

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.

Electron emission from single-walled carbon nanotubes with sharpened bundles

We investigated the influence of grinding as a pretreatment prior to the emitter film formation of single-walled carbon nanotubes (SWNTs) on the field emission and the geometric properties of SWNTs. Field emission from emitter films composed of ground SWNTs was found to be dramatically enhanced as well as to be homogeneous and stable, compared with that from emitter films composed of unground SWNTs. Transmission electron microscopy observations showed that several SWNTs protrude from the ends of ground SWNT bundles. The improved emission current is attributed to the large field enhancement at the sharpened ends of the SWNT bundles.

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. >

Effects of thermal annealing on emission characteristics and emitter surface properties of a Spindt-type field emission cathode

The effects of thermal annealing below 500 °C on Spindt-type molybdenum field emitter arrays were studied through the field emission characteristics and Mo surface analysis. The anode current of the field emitter arrays increases with increasing annealing time and then saturates after a certain period that is shorter for higher-temperature annealing. These phenomena are clearly explained by the molybdenum trioxide (MoO3) desorption revealed by studies using x-ray photoelectron spectroscopy and temperature programmed desorption, and by calculation of MoO3 desorption rates. The MoO3 desorption is the predominant effect for low-temperature annealing and the increase in the anode current is mainly due to lowering of the work function after MoO3 desorption.

EPITAXIAL ORIENTATION OF PTSI GROWN BY PT DEPOSITION ON HEATED SI(001) SUBSTRATE

PtSi film epitaxial orientation and morphology depend greatly on the Si(001) substrate temperature during Pt deposition. 15 nm Pt films were evaporated on the heated substrate in room‐temperature to the 1100 K range. The PtSi on the Si substrate forms a continuous film below 850 K and forms islands at above 920 K. In the entire heated range, except for around 1000 K, the dominant epitaxial orientation is PtSi(110)‖‖Si(001) (A orientation). At around 1000 K, the dominant orientation is PtSi(121)‖‖Si(001) (called B orientation). In the range from 920 to 950 K, B orientation grains partially exist in the predominant A orientation. Below 1000 K, the predominant factor governing the epitaxial orientation is area mismatch, which is the difference between the PtSi and Si superlattice areas at the interface. The predominantly A‐oriented grains observed at above 1050 K can be explained by the superlattice area mismatch concept.

A new concept silicon homojunction infrared sensor

A novel silicon photovoltaic infrared sensor is proposed. It consists of three regions with a homojunction structure that has a flexibility designed barrier height corresponding to the cutoff wavelength. The operation of the sensor is based on infrared absorption and internal photoemission by free-electrons in a conduction band in a degenerated n/sup ++/-type silicon. Results obtained with fabricated sensors have verified the basic operating principle and have shown that the detectable wavelength range extends past 12 mu m.<<ETX>>

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.

EFFECTS OF THERMAL ANNEALING ON EMISSION CHARACTERISTICS AND SURFACE PROPERTIES OF FIELD EMITTER ARRAYS

The effects of thermal annealing below 500 °C on Spindt-type Mo field emitter arrays (FEAs) were studied through emission characteristics and Mo surface analysis. The anode current of the FEAs increases with increasing annealing time and then saturates after a certain period that is shorter for higher-temperature annealing. X-ray photoelectron spectroscopy and temperature programmed desorption show that MoO3 formed on the Mo surface desorbs at around 500 °C. The enhancement of the anode current is caused mainly by MoO3 desorption, since the period required for MoO3 desorption corresponds to that required for current saturation.