US 9,177,992 B2 · Active LED module with LED and transistor formed on same substrate

Abstract

An LED module is disclosed containing an integrated driver transistor (e.g, a MOSFET) in series with an LED. In one embodiment, LED layers are grown over a substrate. The transistor regions are formed over the same substrate. After the LED layers, such as GaN layers, are grown to form the LED portion, a central area of the LED is etched away to expose a semiconductor surface in which the transistor regions are formed. A conductor connects the transistor in series with the LED. Another node of the transistor is electrically coupled to an electrode on the bottom surface of the substrate. In one embodiment, an anode of the LED is connected to one terminal of the module, one current carrying node of the transistor is connected to a second terminal of the module, and the control terminal of the transistor is connected to a third terminal of the module.

Claims18

Dependent claims

A lighting device comprising:

a first light emitting diode (LED) having at least a first LED layer of a first conductivity and a second LED layer of a second conductivity, the first LED layer and the second LED layer being epitaxially grown over a top surface of a semiconductor material;
a first transistor formed over or in the top surface of the semiconductor material, the first transistor having a first current carrying node, a second current carrying node, and a control node,
wherein the first LED surrounds the frist transistor, and the first transistor is substantially centered within the first LED;
and
a first conductor connecting the first current carrying node of the first transistor to the first LED layer to connect the first transistor in series with the LED so that, when a voltage is applied across the second LED layer and the second current carrying node of the first transistor, and the transistor conducts current, current flows laterally through the first transistor and vertically through the LED to illuminate the LED.

2 more elements

A method of forming a light emitting device comprising:

providing a semiconductor material;
growing layers of a first light emitting diode (LED), the layers comprising a first LED layer of a first conductivity and a second LED layer of a second conductivity, the first LED layer and the second LED layer being epitaxially grown over a top surface of the semiconductor material;
forming a first transistor over or in the top surface of the semiconductor material, the first transistor having a first current carrying node, a second current carrying node, and a control node,
wherein the first LED surrounds the first transistor, and the first transistor is Substantially centered within the first LED;
and
forming a first conductor connecting the first current carrying node of the first transistor to the first LED layer to connect the first transistor in series with the LED so that, when a voltage is applied across the second LED layer and the second current carrying node of the first transistor, and the transistor conducts current, current flows laterally through the first transistor and vertically through the LED to illuminate the LED.

3 more elements

Dependencies are inferred from the claim text.

Active LED module with LED and transistor formed on same substrate

Life of this patent

Active LED module with LED and transistor formed on same substrate

Life of this patent

Abstract

Claims18