Abstract: An ohmic electrode for an SiC semiconductor includes a p-type Si layer formed on the surface of a p-type SiC semiconductor, and a metal silicide layer formed on the surface of the Si layer, the metal silicide layer being formed from a metal silicide such as PtSi. The p-type Si layer is preferably formed from p-type Si having a carrier concentration equal to or higher than that of the aforementioned p-type SiC. Preferably, the ohmic electrode is formed as follows: deposition of Si is performed; deposition of a metal silicide is performed by means of laser ablation; laser irradiation is performed to thereby improve ohmic properties and enhance adhesion between the result deposition layer and the p-type SiC semiconductor, and then further deposition of the metal silicide is performed by means of laser ablation.

Abstract: An ohmic electrode for an SiC semiconductor includes a p-type Si layer formed on the surface of a p-type SiC semiconductor, and a metal silicide layer formed on the surface of the Si layer, the metal silicide layer being formed from a metal silicide such as PtSi. The p-type Si layer is preferably formed from p-type Si having a carrier concentration equal to or higher than that of the aforementioned p-type SiC. Preferably, the ohmic electrode is formed as follows: deposition of Si is performed; deposition of a metal silicide is performed by means of laser ablation; laser irradiation is performed to thereby improve ohmic properties and enhance adhesion between the resultant deposition layer and the p-type SiC semiconductor; and then further deposition of the metal silicide is performed by means of laser ablation.

Abstract: A gas sensor having a pn junction including two discrete electrical conductive-type layers, namely, a first semiconductor layer and a second semiconductor layer, disposed in contact with each other. Ohmic electrodes are formed on the respective surfaces of the semiconductor layers. A catalytic layer containing a metallic catalytic component which dissociates hydrogen atom from a molecule having hydrogen atom is formed on one of the ohmic electrodes. The pn junction diode-type gas sensor has a simple constitution, exhibits a small change in diode characteristics with time in long-term service and is capable of detecting a gas concentration of a molecule having a hydrogen atom, for example, H2, NH3, H2S, a hydrocarbon and the like, contained in a sample gas.

Abstract: An ohmic electrode for an SiC semiconductor includes a p-type Si layer formed on the surface of a p-type SiC semiconductor, and a metal silicide layer formed on the surface of the Si layer, the metal silicide layer being formed from a metal silicide such as PtSi. The p-type Si layer is preferably formed from p-type Si having a carrier concentration equal to or higher than that of the aforementioned p-type SiC. Preferably, the ohmic electrode is formed as follows: deposition of Si is performed; deposition of a metal silicide is performed by means of laser ablation; laser irradiation is performed to thereby improve ohmic properties and enhance adhesion between the resultant deposition layer and the p-type SiC semiconductor; and then further deposition of the metal silicide is performed by means of laser ablation.

Abstract: A gas sensor having a pn junction including two discrete electrical conductive-type layers, namely, a first semiconductor layer and a second semiconductor layer, disposed in contact with each other. Ohmic electrodes are formed on the respective surfaces of the semiconductor layers. A catalytic layer containing a metallic catalytic component which dissociates hydrogen atom from a molecule having hydrogen atom is formed on one of the ohmic electrodes. The pn junction diode-type gas sensor has a simple constitution, exhibits a small change in diode characteristics with time in long-term service and is capable of detecting a gas concentration of a molecule having a hydrogen atom, for example, H2, NH3, H2S, a hydrocarbon and the like, contained in a sample gas.