LED, especially a powerful red to yellowish green emitting aluminum gallium indium phosphide LED, has upper cladding structure including thin high ohmic layer

摘要

An LED comprises an upper cladding structure (303) which includes a thin, lightly doped or undoped, high ohmic layer. A novel LED comprises a first conductivity type semiconductor substrate (300) bearing: (a) a first conductivity type AlGaInP lower cladding layer (301; (b) an undoped AlGaInP active layer (302); (c) an upper cladding structure (303) comprising two second conductivity type AlGaInP layers, the lower layer of which is lattice-matched with the substrate and the upper layer of which is thin and has a low dopant concentration to provide a high resistance; and (d) a second conductivity type ohmic contact layer of (AlxGa1-x)yIn1-yP, where x = 0 to 0.1 and y = 0.7 to 1. An Independent claim is also included for a similar LED in which the active layer (302) has a mqw (multiple quantum well) structure with alternating (AlGa)InP quantum wells (3021) and (AlGa)InP barriers (3022).