Abstract: The bipolar transistor includes a heterojunction intrinsic base layer epitaxially grown on a collector layer. The intrinsic base layer is disposed on the collector layer surrounded by an isolation layer, and an N-type impurity layer is formed in a surface portion of the collector layer. The impurity concentration of the N-type impurity layer is higher than the impurity concentration of the collector layer under the N-type impurity layer. Between the N-type impurity layer and the intrinsic base layer, an epitaxially grown layer is formed, where the epitaxially grown layer is lower in impurity concentration than the N-type impurity layer and the intrinsic base layer.

Abstract: A bipolar transistor 120 comprises a substrate 1, a intrinsic base region 11 and an extrinsic base region 12. The intrinsic base region 11 comprises a silicon buffer layer 109 comprised of silicon which is formed on the substrate 1, and a composition-ratio graded base layer 111 which is formed on the silicon buffer layer and comprises silicon and at least germanium and where a composition ratio of the germanium to the silicon varies in a thickness direction of the composition-ratio graded base layer 111. The extrinsic base region 12 comprises an extrinsic base formation layer 113 comprised of silicon which is formed on the substrate and adjacent to the silicon buffer layer. And the thickness of the extrinsic base formation layer 113 is not less than 40 nm.

Abstract: A bipolar transistor includes a Si single crystalline layer serving as a collector, a single crystalline Si/SiGeC layer and a polycrystalline Si/SiGeC layer which are formed on the Si single crystalline layer, an oxide film having an emitter opening portion, an emitter electrode, and an emitter layer. An intrinsic base layer is formed on the single crystalline Si/SiGeC layer, part of the single crystalline Si/SiGeC layer, the polycrystalline Si/SiGeC layer and the Co silicide layer together form an external base layer. The thickness of the emitter electrode is set so that boron ions implanted into the emitter electrode and diffused therein do not reach an emitter-base junction portion.

Abstract: A bipolar transistor 120 comprises a substrate 1, a intrinsic base region 11 and an extrinsic base region 12. The intrinsic base region 11 comprises a silicon buffer layer 109 comprised of silicon which is formed on the substrate 1, and a composition-ratio graded base layer 111 which is formed on the silicon buffer layer and comprises silicon and at least germanium and where a composition ratio of the germanium to the silicon varies in a thickness direction of the composition-ratio graded base layer 111. The extrinsic base region 12 comprises an extrinsic base formation layer 113 comprised of silicon which is formed on the substrate and adjacent to the silicon buffer layer. And the thickness of the extrinsic base formation layer 113 is not less than 40 nm.

Abstract: A bipolar transistor includes a Si single crystalline layer serving as a collector, a single crystalline Si/SiGeC layer and a polycrystalline Si/SiGeC layer which are formed on the Si single crystalline layer, an oxide film having an emitter opening portion, an emitter electrode, and an emitter layer. An intrinsic base layer is formed on the single crystalline Si/SiGeC layer, part of the single crystalline Si/SiGeC layer, the polycrystalline Si/SiGeC layer and the Co silicide layer together form an external base layer. The thickness of the emitter electrode is set so that boron ions implanted into the emitter electrode and diffused therein do not reach an emitter-base junction portion.

Abstract: A bipolar transistor includes a Si single crystalline layer serving as a collector, a single crystalline Si/SiGeC layer and a polycrystalline Si/SiGeC layer which are formed on the Si single crystalline layer, an oxide film having an emitter opening portion, an emitter electrode, and an emitter layer. An intrinsic base layer is formed on the single crystalline Si/SiGeC layer, part of the single crystalline Si/SiGeC layer, the polycrystalline Si/SiGeC layer and the Co silicide layer together form an external base layer. The thickness of the emitter electrode is set so that boron ions implanted into the emitter electrode and diffused therein do not reach an emitter-base junction portion.

Abstract: A method for fabricating a semiconductor crystal that has a first step for forming a semiconductor crystal layer (202) that contains carbon atoms and at least one kind of Group IV element other than carbon on a substrate (201), a second step for adding an impurity that is capable of reacting with oxygen to the semiconductor crystal layer (202), and a third step for removing the carbon atoms contained in the semiconductor crystal layer (202) by reacting the carbon with the impurity. This method makes it possible to fabricate a semiconductor crystal substrate in which the concentration of interstitial carbon atoms is satisfactorily reduced, thus resulting in excellent electrical properties when the substrate is applied to a semiconductor device.

Abstract: The present invention discloses a process of fabricating a semiconductor device comprising the steps of: forming a collector layer of a first conductivity type at a portion of a surface of a semiconductor substrate; forming a collector opening portion in a first insulating layer formed on the semiconductor substrate; epitaxially growing, on the semiconductor substrate of the collector opening portion, a semiconductor layer including a layer of a second conductivity type constituting a base layer; sequentially layering, on the semiconductor substrate, an etching stopper layer against dry etching and a masking layer against wet etching; exposing a part of the etching stopper layer by removing a part of the masking layer by means of dry etching; and by subjecting the exposed etching stopper layer to a wet etching treatment using the remaining masking layer as a mask, forming a base junction opening portion through the etching stopper layer and the masking layer.

Abstract: A method for fabricating a semiconductor crystal that has a first step for forming a semiconductor crystal layer (202) that contains carbon atoms and at least one kind of Group IV element other than carbon on a substrate (201), a second step for adding an impurity that is capable of reacting with oxygen to the semiconductor crystal layer (202), and a third step for removing the carbon atoms contained in the semiconductor crystal layer (202) by reacting the carbon with the impurity. This method makes it possible to fabricate a semiconductor crystal substrate in which the concentration of interstitial carbon atoms is satisfactorily reduced, thus resulting in excellent electrical properties when the substrate is applied to a semiconductor device.

Abstract: A method for fabricating a semiconductor crystal that has a first step for forming a semiconductor crystal layer (202) that contains carbon atoms and at least one kind of Group IV element other than carbon on a substrate (201), a second step for adding an impurity that is capable of reacting with oxygen to the semiconductor crystal layer (202), and a third step for removing the carbon atoms contained in the semiconductor crystal layer (202) by reacting the carbon with the impurity. This method makes it possible to fabricate a semiconductor crystal substrate in which the concentration of interstitial carbon atoms is satisfactorily reduced, thus resulting in excellent electrical properties when the substrate is applied to a semiconductor device.

Abstract: A bipolar transistor includes a Si single crystalline layer serving as a collector, a single crystalline Si/SiGeC layer and a polycrystalline Si/SiGeC layer which are formed on the Si single crystalline layer, an oxide film having an emitter opening portion, an emitter electrode, and an emitter layer. An intrinsic base layer is formed on the single crystalline Si/SiGeC layer, part of the single crystalline Si/SiGeC layer, the polycrystalline Si/SiGeC layer and the Co silicide layer together form an external base layer. The thickness of the emitter electrode is set so that boron ions implanted into the emitter electrode and diffused therein do not reach an emitter-base junction portion.

Abstract: The present invention discloses a process of fabricating a semiconductor device comprising the steps of: forming a collector layer of a first conductivity type at a portion of a surface of a semiconductor substrate; forming a collector opening portion in a first insulating layer formed on the semiconductor substrate; epitaxially growing, on the semiconductor substrate of the collector opening portion, a semiconductor layer including a layer of a second conductivity type constituting a base layer; sequentially layering, on the semiconductor substrate, an etching stopper layer against dry etching and a masking layer against wet etching; exposing a part of the etching stopper layer by removing a part of the masking layer by means of dry etching; and by subjecting the exposed etching stopper layer to a wet etching treatment using the remaining masking layer as a mask, forming a base junction opening portion through the etching stopper layer and the masking layer.

Abstract: There is disclosed a semiconductor device cleaning method involving placing a cleaning solution containing 24 wt. % sulfuric acid, 5 wt. % hydrogen peroxide, 0.02 wt. % hydrogen fluoride, 0.075 wt. % n-dodecylbenzenesulfonic acid, and water into a quartz processing vessel and heating to no more than 100° C. A silicon wafer is immersed into the cleaning solution for 10 minutes and then washed by demineralized water for about 7 minutes. The surfaces of foreign particles on the wafer are etched by hydrogen fluoride, and n-dodecylbenzenesulfonic acid combines with the etched surfaces by sulfate ester bonding. The apparent diameter of the foreign particles increases and the repulsive force caused by zeta potential etc. increases, so that the foreign particles are unlikely to adhere to the surface of the silicon wafer permitting the foreign particles to be easily washed away in a water cleaning step.

Abstract: A method for fabricating an AlGaInP-based visible light laser device by molecular beam epitaxy is described. In this method, a upper clad layer of (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P wherein x and y are, respectively, in the ranges of from 0.5 to 1 and from 0.47 to 0.53 is covered with a protective layer serving also as an etching prevenive layer so that a grooved-type structure using the (Al.sub.x Ga.sub.1-x).sub.y In.sub.1-y P clad layer can be fabricated without involving degradation of the clad layer by contamination with oxygen, nitrogen and the like.

Abstract: An optical phase modulator for use with a fiber optic sensor such as a fiber optic gyroscope includes a piezoelectric vibrator which is asymmetric in at least one cross-sectional shape thereof, a pair of electrodes for applying a voltage to said piezoelectric vibrator, and an optical fiber joined to at least a portion of said piezoelectric vibrator by adhesive bonding. The piezoelectric vibrator has a cavity defined therein, and one of said electrodes is disposed on a surface of said piezoelectric vibrator which defines said axial cavity, the other electrode being disposed on an outer surface of said piezoelectric vibrator. The piezoelectric vibrator may be cylindrical, elliptically cylindrical, or planar in shape. The cavity may be cylindrical or elliptically cylindrical in shape.