Semiconductor circuit having capacitor and thin film transistor, flat panel display including the semiconductor circuit, and method of manufacturing the semiconductor circuit

1. A semiconductor circuit having a capacitor and a thin film transistor (TFT), comprising:

a substrate;

a semiconductor layer and a first capacitor electrode formed on the substrate, the first capacitor electrode being doped to be conductive;

an insulating layer covering the semiconductor layer and the first capacitor electrode;

a gate electrode disposed on the insulating layer and corresponding to a portion of the semiconductor layer, wherein the thickness of the gate electrode is greater than 1000 Å and less than 5000 Å;

a second capacitor electrode disposed on the insulating layer and corresponding to the first capacitor electrode,

wherein the gate electrode comprises a first conductive layer corresponding to the portion of the semiconductor layer and a second conductive layer disposed on the first conductive layer, wherein the second conductive layer is substantially thicker than the first conductive layer and the second capacitor electrode, wherein the first conductive layer and the second capacitor electrode are formed of the same material and wherein the first and second conductive layers are configured to block dopants during an ion doping process and the second capacitor electrode is configured to pass through the dopants during the ion doping process; and

an intermediate insulating layer formed directly on the insulating layer, the second conductive layer and the second capacitor electrode, wherein the intermediate insulating layer includes:

a first portion formed directly over the second conductive layer,

a second portion formed directly over the second capacitor electrode, and

a third portion formed directly over the insulating layer,

wherein a second distance between a top surface of the second portion and a top surface of the substrate is greater than a third distance between a top surface of the third portion and the top surface of the substrate, and

wherein the second distance is less than a first distance between a top surface of the first portion and the top surface of the substrate.

2. The semiconductor circuit of claim 1 , wherein a portion of the semiconductor layer that does not correspond to the gate electrode is doped with the same dopants as the first capacitor electrode.

3. The semiconductor circuit of claim 2 , wherein a doping density of the portion of the semiconductor layer is heavier than a doping density of the first capacitor electrode.

4. The semiconductor circuit of claim 1 , wherein the first conductive layer and the second capacitor electrode have substantially the same thickness.

5. The semiconductor circuit of claim 1 , wherein the semiconductor layer and the first capacitor electrode have substantially the same thickness.

6. The semiconductor circuit of claim 1 , wherein the gate electrode and second capacitor electrode are located at substantially the same distance from the substrate.

7. The semiconductor circuit of claim 1 , wherein the gate electrode and second capacitor electrode are located directly above the semiconductor layer and the first capacitor electrode, respectively.

8. A flat panel display, comprising:

a thin film transistor (TFT) and capacitor circuit including:

a semiconductor layer and a first capacitor electrode formed on a substrate layer, the first capacitor electrode being doped to be conductive,

an insulating layer covering the semiconductor layer and the first capacitor electrode,

a gate electrode disposed on the insulating layer and corresponding to a portion of the semiconductor layer,

a second capacitor electrode disposed on the insulating layer and corresponding to the first capacitor electrode and

an intermediate insulating layer formed directly on the insulating layer, the second conductive layer and the second capacitor electrode,

wherein the gate electrode comprises a first conductive layer corresponding to the portion of the semiconductor layer and a second conductive layer disposed on the first conductive layer,

wherein the second conductive layer is substantially thicker than the first conductive layer and the second capacitor electrode,

wherein the first conductive layer and the second capacitor electrode are formed of the same material and wherein the first and second conductive layers are configured to block dopants during an ion doping process and the second capacitor electrode is configured to pass through the dopants during the ion doping process,

wherein the thickness of the gate electrode is greater than 1000 Å and less than 5000 Å,

wherein the intermediate insulating layer includes:

a first portion formed directly over the second conductive layer,

a second portion formed directly over the second capacitor electrode, and

a third portion formed directly over the insulating layer,

wherein a second distance between a top surface of the second portion and a top surface of the substrate is greater than a third distance between a top surface of the third portion and the top surface of the substrate, and

wherein the second distance is less than a first distance between a top surface of the first portion and the top surface of the substrate;

source and drain electrodes contacting the semiconductor layer; and

a light emitting device electrically connected to at least one of the source and drain electrodes.