Abstract: The exhaust gas purification device includes a substrate, a first catalyst layer, and a second catalyst layer. The substrate includes an upstream end and a downstream end. The first catalyst layer contains first catalyst particles and lies on the substrate across a first region extending between the upstream end and a first position. The first position is at a first distance from the upstream end toward the downstream end. The second catalyst layer contains second catalyst particles and lies on the first catalyst layer across the first region. The second catalyst layer is provided with pores. Pore connectivity of the second catalyst layer is 5% to 35%. A mean value of areas of the pores of the second catalyst layer in a cross-sectional backscattered electron image of the second catalyst layer may be 0.7 ?m2 to 9.0 ?m2.

Abstract: A method of controlling characteristics of a compound semiconductor device, whereby the compound semiconductor device is formed so as to include a plurality of resistors having the same ratio of a difference between a surface area of a corresponding resistivity region and the combined overlapping surface area of a corresponding pair of electrodes to the combined overlapping surface area of the corresponding pair of electrodes. In this manner, a resistivity of a resistor is precisely controlled.

Abstract: A compound semiconductor device is formed having a plurality of FETs exhibiting the same electrode ratio of a difference between a surface area the active region and the combined overlapping surface area of the source and drain ohmic electrodes to the combined overlapping surface area of the source and drain ohmic electrodes. As such, precise control of a threshold voltage of the FETs is achieved. The compound semiconductor device is also formed so as to include a plurality of resistors having the same ratio of a difference between a surface area of the resistivity region and the combined overlapping surface area of the pair electrodes to the combined overlapping surface area of the pair electrodes. In this manner, a resistivity of the resistor is precisely controlled.

Abstract: A semiconductor device fabrication process includes forming a Schottky layer, a cap layer covering the surface of the Schottky layer, and a Schottky electrode of a two-level structure having a lower portion that penetrates through the cap layer and reaches the Schottky layer, and having an upper portion larger than the lower portion in cross-sectional area and that overlies the cap layer. With this construction, surface defects are unlikely to occur, so that a highly reliable semiconductor device can be fabricated.

Abstract: A compound semiconductor device is formed having a plurality of FETs exhibiting the same electrode ratio of a difference between a surface area of the active region and the combined overlapping surface area of the source and drain ohmic electrodes to the combined overlapping surface area of the source and drain ohmic electrodes. As such, precise control of a threshold voltage of the FETs is achieved. The compound semiconductor device is also formed so as to include a plurality of resistors having the same ratio of a difference between a surface area of the resistivity region and the combined overlapping surface area of the pair electrodes to the combined overlapping surface area of the pair electrodes. In this manner, a resistivity of the resistor is precisely controlled.

Abstract: A semiconductor device according to the invention comprises a Schottky layer, a cap layer covering the surface of the Schottky layer, and a Schottky electrode of a two-level structure, having an under structure penetrating through the cap layer and reaching the Schottky layer, and an upper structure larger than the under structure in a cross-sectional area and overlying the cap layer. With such a construction as described, surface defect is unlikely to occur, and therefore, a highly reliable semiconductor device can be fabricated.

Abstract: A compound semiconductor device is formed having a plurality of FETs exhibiting the same electrode ratio of a difference between a surface area of the active region and the combined overlapping surface area of the source and drain ohmic electrodes to the combined overlapping race area of the source and drain ohmic electrodes. As such, precise control of a threshold voltage of the FETs is achieved The compound semiconductor device is also formed, so as to include a plurality of resistors having the same ratio of a difference between a surface area of the resistivity region and the combined overlapping surface area of the pair electrodes to the combined overlapping surface area of the pair electrodes. In this manner, a resistivity of the resistor is precisely controlled.

Abstract: A semiconductor device includes a Schottky layer, a cap layer covering the surface of the Schottky layer, and a Schottky electrode of a two-level structure. The Schottky electrode has a lower portion that penetrates through the cap layer and reaches the Schottky layer, and has an upper portion larger than the lower portion in cross-sectional area and that overlies the cap layer. With this construction, surface defects are unlikely to occur, so that a highly reliable semiconductor device can be fabricated.

Abstract: A compound semiconductor device is formed having a plurality of FETs exhibiting the same electrode ratio of a difference between a surface area of the active region and the combined overlapping surface area of the source and drain ohmic electrodes to the combined overlapping surface area of the source and drain ohmic electrodes. As such, precise control of a threshold voltage of the FETs is achieved. The compound semiconductor device is also formed so as to include a plurality of resistors having the same ratio of a difference between a surface area of the resistivity region and the combined overlapping surface area of the pair electrodes to the combined overlapping surface area of the pair electrodes. In this manner, a resistivity of the resistor is precisely controlled.

Abstract: A thermoplastic resin composition for cleaning a shaping apparatus such as an extrude by a simple operation, comprising 2-30% by weight of a sodium salt of sulfonic acid, 0.5-10% by weight of a water-repellent compound and a thermoplastic resin and as an optional component, finely ground inorganic compound having a particle size of 0.005 to 10 .mu.m.