1. A method of forming a semiconductor diode, said method comprising: forming a first region of silicon that is doped with a first material having a first conductivity; forming a second region of silicon over the first region, the second region is not intentionally doped; forming a third region of silicon over the second region; doping the third region with a second material having a second conductivity that is opposite from the first conductivity; forming a region of SiGe over the third region of silicon; and forming a top contact over the region of SiGe.