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Katoda, Takashi

Takashi Katoda

Masato Kishi

The present invention is directed to photonic devices which emit or absorb light with a wavelength shorter than that GaN photonic devices can emit or absorb. The devices according to the present invention are formed using molybdenum oxide of a high purity as a light emitting region or a light absorbing region. New inexpensive photonic devices which emit light with a wavelength from blue to deep ultraviolet rays are realized. The devices according to the present invention can be formed at a temperature relating low such as 700&#xb0; C.

Photonic devices formed of high-purity molybdenum oxide

The present invention directed to photonic devices which emit or absorb light with a short wavelength formed using molybdenum oxide grown on substrates which consist of materials selected from element semiconductors, III-V or II-IV compound semiconductors, IV compound semiconductors, organic semiconductors, metal crystal and their derivatives or glasses. New inexpensive photonic devices which emit light with a wavelength from blue to deep ultraviolet rays are realized.

Photonic devices formed on substrates and their fabrication methods

The present invention relates to semiconductor electronic devices including molybdenum oxide formed on substrates which consist of materials which are used in known semiconductor electronic devices. The present invention relates to also a new method to fabricate said electronic devices on substrates made of materials which have been used in usual electronic and photonic devices. Suitable substrates consist of materials such as element semiconductors such as silicon and germanium, III-V compound semiconductors such as gallium arsenide and gallium phosphide, II-IV compound semiconductors such as zinc oxide, IV compound semiconductors, organic semiconductors, metal crystals and their derivatives or glasses.

Electronic devices formed on substrates and their fabrication methods

The present invention is directed to a new semiconductor film comprising of metal oxide grown on a substrate and its fabrication method. The metal oxide is comprised of molybdenum oxide which is very useful to fabricate electronic devices with high withstand voltages and photonic and electronic hostile-environment devices. An important aspect of the present invention is that the molybdenum oxide film is formed on a substrate made of material which has been used in usual electronic and photonic devices. The most popular material is silicon. Another important aspect of the present invention is a new method to form a molybdenum oxide film on a substrate.

Metal oxide layer formed on substrates and its fabrication methods

The present invention is to provide an improved surge protector device. The present invention's surge protector device basically has a plurality of metal bars which are combined to a single body by a continuous high-resistive film of semiconductor crystal so that there is no gap between adjacent metal bars; and electrodes formed on the endmembers of the said metal bars composing the single body. Thus, the present invention's surge protector device is fabricated so as to have no air gap between adjacent ones of the metal bars. As a result, the present invention's protector device can operate in such a way that the surge protector device changes from a non-conductive state to a conductive state due to breakdown in depletion region accompanying the semiconductor crystal when the voltage across the electrodes exceeds a threshold voltage because of a surge.

Surge protector device and its fabrication method

The present invention is directed to electronic devices comprising high-purity molybdenum oxide in at least a part of the devices. The devices according to the present such a bipolar transistor, a field effect transistor and a thyristor have a high withstand voltage. The present invention is directed also hostile-environment electron devices formed using high-purity molybdenum oxide. The devices according the present invention can be fabricated at a relatively lower temperature such as 700&#xb0; C. than that at which GaN or SiC devices are fabricated, the at is a temperature higher than 1000&#xb0; C.

Electronic devices formed of high-purity molybdenum oxide

The present invention is directed to a main element of a surge protector device and its fabrication method which uses breakdown phenomenon of a single high resistive film. A breakdown voltage and a place where breakdown occurs can be precisely controlled. The surge protector device changes from its non-conductive state to conductive state very quickly when a surge is induced and returns quickly to the non-conductive state when a surge is removed if said element is surrounded by oxidizing agent. The main element of the surge protector device of the present invention has a single high resistive film on a single metal bar. The high resistive film has a part or parts where electric field concentrates when a surge induced. A breakdown voltage can be controlled precisely by controlling a size including a thickness of the high resistive film of the part. The part is called a fuse part. The main element includes also at least two parts on said metal bar which are continuous to said fuse part. Electrodes are formed on said at least two parts. Therefore said at least two parts are called pad parts.

Main element of a surge protector device

In the fabrication of a surge protector device which utilizes breakdown phenomena of a resistive film, a case which fixes metal bars in it, makes electrical contacts with the metal bars and contains oxidizing and refractory agents, a cap, metal bars and oxidizing and refractory agents are prepared in advance. In the fabrication process of the surge protector device using these elements, a step to control the force applied to the cap, the metal bars and the case so that the force applied to the interface between the resistive films and the mechanical contacts which form electrodes to the metal bars can be controlled. Automation process to fabricate the surge protector device will be realized and efficient fabrication of the precise surge protector device will be also realized. A surge protector device whose breakdown voltage is precisely controlled will be realized reproducibly.

Fabrication method of surge protector device and the device fabricated by the method

A method for manufacturing a semiconductor device comprises evaporating phosphorus on a silicon substrate to form a thin phosphorus layer and growing gallium phosphide on the substrate having the thin phosphorus layer, heterojunction being defined between the substrate and the semiconductor layer only in the region where the thin film had been formed prior to the growth of gallium phosphide.

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Kochi, Japan

Takashi Katoda