Abstract: In the method for fabricating a semiconductor device of the present invention, a collector layer of a first conductivity type is formed in a region of a semiconductor substrate sandwiched by device isolation. A collector opening is formed through a first insulating layer deposited on the semiconductor substrate so that the range of the collector opening covers the collector layer and part of the device isolation. A semiconductor layer of a second conductivity type as an external base is formed on a portion of the semiconductor substrate located inside the collector opening, while junction leak prevention layers of the same conductivity type as the external base are formed in the semiconductor substrate. Thus, the active region is narrower than the collector opening reducing the transistor area, while minimizing junction leak.

Abstract: In the method for fabricating a semiconductor device of the present invention, a collector layer of a first conductivity type is formed in a region of a semiconductor substrate sandwiched by device isolation. A collector opening is formed through a first insulating layer deposited on the semiconductor substrate so that the range of the collector opening covers the collector layer and part of the device isolation. A semiconductor layer of a second conductivity type as an external base is formed on a portion of the semiconductor substrate located inside the collector opening, while junction leak prevention layers of the same conductivity type as the external base are formed in the semiconductor substrate. Thus, the active region is narrower than the collector opening reducing the transistor area, while minimizing junction leak.

Abstract: In the method for fabricating a semiconductor device of the present invention, a collector layer of a first conductivity type is formed in a region of a semiconductor substrate sandwiched by device isolation. A collector opening is formed through a first insulating layer deposited on the semiconductor substrate so that the range of the collector opening covers the collector layer and part of the device isolation. A semiconductor layer of a second conductivity type as an external base is formed on a portion of the semiconductor substrate located inside the collector opening, while junction leak prevention layers of the same conductivity type as the external base are formed in the semiconductor substrate. Thus, the active region is narrower than the collector opening reducing the transistor area, while minimizing junction leak.

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.