Conductive elements for thin film transistors used in a flat panel display

• US 7,317,206 B2
• Filed: 01/29/2004
• Issued: 01/08/2008
• Est. Priority Date: 03/12/2003
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung SDI Company Limited
• Inventors: Kim, Tae-Sung
• Primary Examiner(s): Erdem; Fazli
• Application Number:
  US10/766,564
• Publication Number:
  US 20050072973A1
• Time in Patent Office: 1,440 Days
• Field of Search: 257/72, 257/73, 257/70, 257/71, 257/75, 257/57, 257/58, 257/59, 257/60, 257/61
• US Class Current: 257/59
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT

Abstract

Provided is a structure for conductive members in a TFT display. The structure is aluminum based and is heat treated. When heat treated, no hillocks are formed because of the presence of a titanium layer. Furthermore, TiAl₃ is not formed because of the presence of a TiN diffusion layer between the aluminum and the Ti layers. This novel structure has a low resistivity and is therefore suited for large displays that use thin film transistors to drive the pixels.

Claims

1. A flat panel display, comprising a plurality of sub-pixels driven by thin film transistors, each of the thin film transistors including a source electrode, a drain electrode, a gate electrode, and a polysilicon semiconductor layer and each of the sub-pixels including a first electrode, a second electrode, and an emitting layer disposed between the first electrode and the second electrode, wherein one of the source electrode and the drain electrode includes:

a first titanium layer contacting the semiconductor layer;

an aluminum-based metal layer arranged on the first titanium layer;

a second titanium layer arranged on the aluminum-based metal layer and contacting the first electrode;

a first titanium nitride layer disposed between the first titanium layer and the aluminum-based metal layer, the first titanium nitride layer preventing titanium from the first titanium layer and aluminum from the aluminum-based metal layer reacting with each other; and

a second titanium nitride layer disposed between the second titanium layer and the aluminum-based metal layer, the second titanium nitride layer preventing titanium from the second titanium layer and aluminum from the aluminum-based metal layer reacting with each other;

wherein the titanium nitride layers contain 5 to 85 wt % of nitrogen.

2. The flat panel display of claim 1, wherein the first titanium nitride layer has a thickness of about 100 to 600 Å

.

3. The flat panel display of claim 1, wherein the first titanium nitride layer has a thickness of about 100 to 400 Å

.

4. The flat panel display of claim 1, wherein the second titanium nitride layer has a thickness of about 200 to 600 Å

.

5. The flat panel display of claim 1, wherein the second titanium nitride layer has a thickness of about 300 Å

.

6. A flat panel display, comprising a plurality of sub-pixels driven by thin film transistors, each of the thin film transistors including a source electrode, a drain electrode, a gate electrode, and a polysilicon semiconductor layer each of the sub-pixels including a first electrode, a second electrode, and an emitting layer disposed between the first electrode and the second electrode, wherein one of the source electrode and the drain electrode includes:

a first titanium layer contacting the semiconductor layer;

an aluminum-based metal layer arranged on the first titanium layer;

a second titanium layer arranged on the aluminum-based metal layer and contacting the first electrode;

a first titanium nitride layer disposed between the first titanium layer and the aluminum-based metal layer, the first titanium nitride layer preventing titanium from the first titanium layer and aluminum from the aluminum-based metal layer reacting with each other; and

a second titanium nitride layer disposed between the second titanium layer and the aluminum-based metal layer, the second titanium nitride layer preventing titanium from the second titanium layer and aluminum from the aluminum-based metal layer reacting with each other;

wherein the aluminum-based metal layer is an aluminum alloy containing about 0.5 to 5 wt % of one element being selected from the group consisting of silicon, copper, neodymium, platinum, and nickel.

7. The flat panel display of claim 6, wherein the aluminum-based metal layer is an aluminum-silicon alloy containing about 2 wt % of silicon.