Epitaxial gallium nitride based light emitting diode and method of making thereof
A light emitting diode includes a n-doped region, a p-doped region, and a light emitting region located between the n-doped region and a p-doped region. The n-doped region includes a first GaN layer, at least one n-doped second GaN layer located over the first GaN layer, an AlGaN dislocation blocking layer located over the at least one n-doped second GaN layer, and a n-doped third GaN layer located over the AlGaN dislocation blocking film.
1. A light emitting diode (LED), comprising:
a n-doped region;
a p-doped region; and
a light emitting region located between the n-doped region and a p-doped region, wherein the n-doped region comprises a first GaN layer, at least one n-doped second GaN layer located over the first GaN layer, an AlGaN dislocation blocking layer located over the at least one n-doped second GaN layer, and a n-doped third GaN layer located over the AlGaN dislocation blocking film;
wherein the p-type region comprises:
an epitaxial low temperature p-type layer located on the light emitting region;
an epitaxial high temperature heavily doped p+ type layer located on the low temperature p-type layer;
an epitaxial first high temperature p-type layer located on the high temperature heavily doped p+ type layer;
an epitaxial second high temperature p-type layer located on the first high temperature p-type layer, wherein the first and the second high temperature p-type layers include at least one p-type GaN layer and at least one p-type AlGaN layer; and
an epitaxial heavily doped contact layer located on the second high temperature p-type layer, and having a higher dopant concentration than the high temperature heavily doped p+ type layer.
2. The LED of claim 1 , wherein:
the low temperature p-type layer comprises a magnesium doped p-type GaN, InGaN or AlGaN layer;
the high temperature heavily doped p+ type layer comprises a magnesium doped p+ GaN layer which is deposited at a higher temperature than the low temperature p-type layer;
the first high temperature p-type layer comprises a magnesium doped p-type GaN or AlGaN layer which is deposited at a higher temperature than the low temperature p-type layer;
the second high temperature p-type layer comprises a magnesium doped p-type AlGaN layer or a p-type GaN/AlGaN superlattice; and
the heavily doped contact layer comprises a magnesium doped p++ GaN or InGaN layer, a magnesium and silicon co-doped p++ GaN or InGaN layer, or a silicon doped n++ GaN or InGaN layer which forms a tunnel diode with the second high temperature p-type layer.