Image Number 12 for United States Patent #5580797.
A lateral bipolar transistor capable of forming a narrow-sized diffusion region, such as a base width, is disclosed. The transistor exhibits no scattering in the direction of the depth of the width of the diffusion region. Emitter resistance is reduced by varying an impurity diffusion source at substantially a uniform concentration in a semiconductor portion and forming a diffusion region by diffusion from the impurity diffusion source. The bipolar transistor has an SOI structure. A method of making such device is also disclosed.