Patent attributes
A two-terminal mesa phototransistor and a method for making it are disclosed. The photo transistor has a mesa structure having a substantially planar semiconductor surface. In the mesa structure is a first semiconductor region of a first doping type, and a second semiconductor region of a second doping type opposite to that of the first semiconductor region, forming a first semiconductor junction with the first region. In addition, a third semiconductor region of the first doping type forms a second semiconductor junction with the second region. The structure also includes a dielectric layer. The second semiconductor region, first semiconductor junction, and second semiconductor junction each has an intersection with the substantially planar semiconductor surface. The dielectric covers, and is in physical contact with, all of the intersections.