Vertical stacks of light emitting diodes and control transistors and method of making thereof
A light emitting device includes a vertical stack of a light emitting diode and a field effect transistor that controls the light emitting diode. An isolation layer is present between the light emitting diode and the field effect transistor, and an electrically conductive path electrically shorts a node of the light emitting diode to a node of the field effect transistor. The field effect transistor may include an indium gallium zinc oxide (IGZO) channel and may be located over the isolation layer. Alternatively, the field effect transistor may be a high-electron-mobility transistor (HEMT) including an epitaxial semiconductor channel layer and the light emitting diode may be located over the HEMT.
1. A light emitting device, comprising:
an epitaxial substrate;
a high-electron-mobility transistor (HEMT) located on the epitaxial substrate and comprising an epitaxial semiconductor channel layer;
at least one isolation layer located over the HEMT;
a light emitting diode comprising an n-doped semiconductor material layer, a light-emitting active region, and a p-doped semiconductor material layer, wherein the light-emitting active region comprises an epitaxial semiconductor material in epitaxial alignment with the at least one isolation layer; and
an electrically conductive path that electrically shorts a node of the light emitting diode to a node of the HEMT,
wherein the HEMT and the light emitting diode have an areal overlap in a plan view,
wherein the at least one isolation layer comprises an epitaxial dielectric material in epitaxial alignment with the epitaxial semiconductor channel layer, and
wherein the at least one isolation layer comprises a layer stack including, from bottom to top:
a first graded aluminum gallium nitride layer in which an atomic concentration of aluminum increases with a vertical distance from the epitaxial substrate;
an aluminum nitride layer located on the first graded aluminum gallium nitride layer and including aluminum nitride as the epitaxial dielectric material; and
a second graded aluminum gallium nitride layer in which an atomic concentration of aluminum decreases with a vertical distance from the epitaxial substrate.
2. The light emitting device of claim 1 , wherein the electrically conductive path comprises a contact via structure that extends through the at least one isolation layer.
3. The light emitting device of claim 2 , wherein the electrically conductive path further comprises a conductive line structure that is located above a top surface of the at least one isolation layer and contacts a top surface of the contact via structure.
4. The light emitting device of claim 2 , wherein a bottom surface of the contact via structure contacts a source electrode of the HEMT or a drain electrode of the HEMT.
5. The light emitting device of claim 2 , further comprising a dielectric liner laterally surrounding the conductive via structure and extending through each of the at least one isolation layer.
6. A light emitting device, comprising:
an epitaxial substrate;
a high-electron-mobility transistor (HEMT) located on the epitaxial substrate and comprising an epitaxial semiconductor channel layer;
at least one isolation layer located over the HEMT;
a light emitting diode comprising an n-doped semiconductor material layer, a light-emitting active region, and a p-doped semiconductor material layer, wherein the light-emitting active region comprises an epitaxial semiconductor material in epitaxial alignment with the at least one isolation layer; and
an electrically conductive path that electrically shorts a node of the light emitting diode to a node of the HEMT,
wherein the at least one isolation layer comprises an epitaxial dielectric material in epitaxial alignment with the epitaxial semiconductor channel layer; and
wherein the at least one isolation layer comprises a layer stack including, from bottom to top:
a first graded aluminum gallium nitride layer in which an atomic concentration of aluminum increases with a vertical distance from the epitaxial substrate;
an aluminum nitride layer located on the first graded aluminum gallium nitride layer and including aluminum nitride as the epitaxial dielectric material; and
a second graded aluminum gallium nitride layer in which an atomic concentration of aluminum decreases with a vertical distance from the epitaxial substrate.