Bipolar transistor, semiconductor device having bipolar transistors

A bipolar transistor comprising:

• a first conductivity type semiconductor substrate having a main surface;
• a second conductivity type semiconductor layer formed on the main surface of said semiconductor substrate;
• a second conductivity type buried diffusion layer formed extending in both said semiconductor layer and said semiconductor substrate;
• a second conductivity type base region formed in a surface of said semiconductor layer located above said buried diffusion layer;
• a collector region composed of a first conductivity type first region formed just below a bottom of said base region so as to have a bottom face within said buried diffusion layer and a first conductivity type second region extending through said base region so as to surround said base region and reach said first region;
• and
• a first conductivity type emitter region formed in at surface of said base region.

A semiconductor device having a bipolar transistor comprising:

• a first conductivity type semiconductor substrate having a main surface;
• a second conductivity type semiconductor layer formed on the main surface of said semiconductor substrate;
• a second conductivity type buried diffusion layer formed extending in both said semiconductor layer and said semiconductor substrate;
• a second conductivity type base region formed in a surface of said semiconductor layer located above said buried diffusion layer;
• a collector region composed of a first conductivity type first region formed below a bottom of said base region so as to have a bottom face within buried diffusion layer and a first conductivity type second region formed within said semiconductor layer so as to surround side ends of said base region and reach said first region, said second region having a first plane width smaller than a thickness of said semiconductor layer;
• a first conductivity type emitter region formed in a surface of said base region;
• and
• a first conductivity type element isolation region formed within said semiconductor layer surrounding said collector region and said buried diffusion layer, said element isolation region having a second plane width greater than or equal to the thickness of said semiconductor layer and extending through said semiconductor layer so as to reach the main surface of said semiconductor substrate.

A bipolar transistor comprising:

• a first conductivity type semiconductor substrate having a main surface;
• a second conductivity type semiconductor layer formed on the main surface of said semiconductor substrate;
• a second conductivity type buried diffusion layer formed extending in both said semiconductor layer and said semiconductor substrate;
• a second conductivity type base region formed in a surface of said semiconductor layer located above said buried diffusing layer;
• a collector region composed of a first conductivity type first region and a tubular shaped first conductivity type second region, said first region being formed just below a bottom of said base region so as to have a bottom face within said buried diffusion layer and being constructed such that a concentration of a first conductivity type impurity contained in the bottom thereof is lower than that of a first conductivity type impurity contained in a portion other than the bottom thereof and said second region being formed so as to surround side ends of said base region and so as to extend through said semiconductor layer to reach the first region;
• and
• a first conductivity type emitter region formed in a surface of said base region, wherein a periphery of the first region of the collector is positioned more inward than that of the second region of the collector region, wherein said second region includes lower end corners, a concentration of a first conductivity type impurity contained in said lower end corners of said second region is lower than that of a first conductivity type impurity contained in portions in said second region adjacent to said lower end corners thereof.

A bipolar transistor comprising:

• a first conductivity type semiconductor substrate having a main surface;
• a second conductivity type semiconductor layer formed on the main surface of said semiconductor substrate;
• a second conductivity type buried diffusion layer formed extending in both said semiconductor layer and said semiconductor substrate;
• a second conductivity type base region formed in a surface of said semiconductor layer located above said buried diffusion layer;
• a collector region composed of a first conductivity type first region and a tubular shared first conductivity type second region, said first region being formed just below a bottom of said base region so as to have a bottom face within said buried diffusion layer and being constructed such that a concentration of a first conductivity type impurity contained in the bottom thereof is lower than that of a first conductivity type impurity contained in a portion other than the bottom thereof and said second region being formed so as to surround side ends of said base region and so as to extend through said semiconductor layer to reach the first region;
• and
• a first conductivity type emitter region formed in a surface of said base region, wherein a periphery of the first region of the collector is positioned more inward than that of the second region of the collector region, wherein said second region has a first plane width smaller than a thickness of said semiconductor layer and overlaps only an upper end portion of said first region, and a first conductivity type element isolation region is formed within said semiconductor layer so as to surround said collector region and said buried diffusion layer and have a second plane width greater than or equal to the thickness of said semiconductor layer and so as to extend through said semiconductor layer to reach the main surface of said semiconductor substrate.

A bipolar transistor comprising:

• a first conductivity type semiconductor substrate having a main surface;
• a second conductivity type semiconductor layer formed on the main surface of said semiconductor substrate;
• a second conductivity type buried diffusion layer formed extending in both said semiconductor layer and said semiconductor substrate;
• a second conductivity type base region formed in a surface of said semiconductor layer located above said buried diffusion layer;
• a collector region composed of a first conductivity type first region and a first conductivity type second region, said first region being formed just below a bottom of said base region so as to have a bottom face within said buried diffusion layer and a height of an upper surface of said first region extending from an interface between said semiconductor layer and said semiconductor substrate being two-third or more the thickness of said semiconductor layer and said second region being formed within said semiconductor layer so as to surround side ends of said base region and reach said first region;
• and
• a first conductivity type emitter region formed in a surface of said base region.

A semiconductor device having a bipolar transistor, comprising:

• a first conductivity type semiconductor substrate having a main surface;
• a second conductivity type semiconductor layer formed on the main surface of said semiconductor substrate;
• first and second buried diffusion layers each formed extending in both said semiconductor layer and said semiconductor substrate with an interval defined therebetween and respectively containing second conductivity type impurity identical in concentration to each other;
• a first conductivity type first base region formed in a surface of said semiconductor layer located above said first buried diffusion layer;
• a second conductivity type first emitter region formed in a surface of said first base region;
• a first conductivity type element isolation region surrounding a first collector region within said semiconductor layer around said first base region, said element isolation region extending through said semiconductor layer so as to reach said semiconductor substrate;
• a second conductivity type second base region formed in a surface of said semiconductor layer located above said second buried diffusion layer;
• a second collector region composed of a first conductivity type first region and a first conductivity type second region, said first region being formed just below a bottom of said second base region so as to have a bottom face within said second buried diffusion layer and a height (H) of an upper surface of said first region from an interface between said semiconductor layer and said semiconductor substrate being two-third or more the thickness of said semiconductor layer and said second region being formed within said semiconductor layer so as to surround side ends of said second base region, having a diffusion depth equal to that of said first base region and reach the first region;
• and
• a first conductivity type second emitter region formed in a surface of said second base region.