Patent ID: 7638820
Filing Date: 2009-12-29
Classification: H01L

Abstract:
1. A semiconductor device comprising: a first active layer including a first compound semiconductor material and having a first conductivity type dopant; a second active layer including a second compound semiconductor material and having a second conductivity type dopant opposite the first conductivity type, wherein the second active layer contacts the first active layer; a third active layer including a third compound semiconductor material and having the first conductivity type dopant, wherein the third active layer contacts the second active layer, and a combination of the first, second, and third active layer are at least part of a transistor; an opening defined by said second and third active layers, said opening extending through the third active layer, said opening contacting and terminating within the second active layer; one or more sidewall insulating layers within the opening to isolate the opening from the adjacent third layer a fourth compound semiconductor material at least partially within the opening and on the second active layer, wherein the fourth compound semiconductor material has the second conductivity type dopant and a dopant concentration higher than the dopant concentration of the second active layer and is electrically connected to the second active layer; and a layer of insulating material on the third layer and over the fourth layer and comprising first and second sets of metal contacts, said contacts separated from each other by said insulating material layer with one set of metal contacts in electrical contact with the third layer, the other set of contacts in direct electrical contact with the fourth layer, wherein said fourth layer lacks a barrier layer.