Drive circuit and organic light-emitting diode display each having switching transistor without etch stopping layer on oxide semiconductor

• US 10,297,651 B2
• Filed: 08/18/2015
• Issued: 05/21/2019
• Est. Priority Date: 09/04/2014
• Status: Active Grant

• Current Assignee: Shanghai Tianma Micro-Electronics Company Limited (Tianma Microelectronics Company Limited), Tianma Microelectronics Company Limited
• Original Assignee: Shanghai Tianma Micro-Electronics Company Limited (Tianma Microelectronics Company Limited), Tianma Microelectronics Company Limited
• Inventors: Zhai, Yingteng, Wu, Yong
• Primary Examiner(s): Jung, Michael
• Application Number:
  US14/829,390
• Publication Number:
  US 20160071912A1
• Time in Patent Office: 1,372 Days
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 27/1251 comprising TFTs having a different architecture, e.g. top- and bottom gate TFTs
• CPC Class Codes: H01L 27/1288 employing particular masking sequences or specially adapted masks, e.g. half-tone mask
• CPC Class Codes: H01L 29/66765 Lateral single gate single channel transistors with inverted structure, i.e. the channel layer is formed after the gate
• CPC Class Codes: H01L 29/7781 with inverted single heterostructure, i.e. with active layer formed on top of wide bandgap layer, e.g. IHEMT
• CPC Class Codes: H01L 29/78669 with inverted-type structure, e.g. with bottom gate
• CPC Class Codes: H01L 29/78678 with inverted-type structure, e.g. with bottom gate
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/124 Insulating layers formed between TFT elements and OLED elements

Abstract

A drive circuit, an organic light-emitting diode display, and methods for fabricating the same are provided. The drive circuit includes: a driving transistor, including a first gate, a first semiconductor layer disposed above the first gate, an etch stopping layer disposed on the first semiconductor layer, and a first source and a first drain which are disposed on the two sides of the first semiconductor layer, the first semiconductor layer being made of oxide semiconductor material; and a switching transistor, including a second gate, a second semiconductor layer disposed above the second gate, and a second source and a second drain which are disposed on two sides of the second semiconductor layer, the second semiconductor layer being made of oxide semiconductor material. In the drive circuit, reliability and uniformity of the drive transistors are improved, and parasitic capacitance of the switching transistor decreases.

Claims

1. A drive circuit for an OLED display panel, comprising:

a driving transistor, comprising;

a first gate;

a first dielectric layer disposed on the first gate;

a first semiconductor layer disposed on the first dielectric layer and patterned into a channel structure above the first gate;

an etch stopping layer disposed on the first semiconductor layer, wherein the etch stopping layer comprises a lower layer and an upper layer directly on top of the lower layer, wherein the lower layer is made of a metallic oxide, and wherein the upper layer is made of a nonmetallic compound; and

a first source and a first drain disposed on two sides of the first semiconductor layer and the etch stopping layer, wherein the first source and the first drain leave a first area exposed on the upper surface, the first source is composed of a first section, a second section, a third section, a fourth section and a fifth section, the first section is disposed on an upper surface of the upper layer, the second section is disposed on a side surface of the etch stopping layer, the third section is disposed on an upper surface of the first semiconductor layer, the fourth section is disposed on a side surface of the first semiconductor layer, and the fifth section is disposed on an upper surface of the first dielectric layer;

a switching transistor, comprising;

a second gate;

a second dielectric layer disposed on the second gate;

a second semiconductor layer disposed on the second dielectric layer and patterned into a channel structure above the second gate; and

a second source and a second drain disposed on two sides of the second semiconductor layer, wherein the second source and the second drain leave a second area exposed on the second semiconductor layer, the second source is composed of a sixth section, a seventh section and an eighth section, the sixth section is disposed on an upper surface of the second semiconductor layer, the seventh section is disposed on a side surface of the second semiconductor layer, and the eighth section is disposed on an upper surface of the second dielectric layer;

and

a third dielectric layer disposed on top of the driving transistor and the switching transistor, wherein the third dielectric layer is disposed to cover the full first area and the full second area in contact with the etch stopping layer in the driving transistor and the second semiconductor layer in the switching transistor;

wherein the first semiconductor layer and the second semiconductor layer are made of an oxide semiconductor material.

2. The drive circuit according to claim 1, wherein the metallic oxide comprises one of alumina, titanium oxide and yttrium oxide.

3. The drive circuit according to claim 1, wherein the nonmetallic compound comprises at least one of silicon oxide, silicon nitride and silicon oxynitride.

4. The drive circuit according to claim 1, wherein a thickness of the etch stopping layer in the driving transistor is in a range of 300 Å

-3000 Å

.

5. The drive circuit according to claim 1, wherein a thickness of the lower layer of the etch stopping layer in the driving transistor is in a range of 100 Å

-1000 Å

, and a thickness of the upper layer is in a range of 100 Å

-1000 Å

.

6. An organic light-emitting diode display, comprising:

a substrate;

a drive circuit disposed on the substrate, wherein the drive circuit comprises a driving transistor, a switching transistor and

an organic light-emitting diode disposed on the substrate;

wherein the driving transistor comprises;

a first gate;

a first dielectric layer disposed on the first gate;

a first semiconductor layer disposed on the first dielectric layer and patterned into a channel structure above the first gate;

an etch stopping layer disposed on the first semiconductor layer, wherein the etch stopping layer comprises a lower layer and an upper layer directly on top of the lower layer, wherein the lower layer is made of a metallic oxide, and wherein the upper layer is made of a nonmetallic compound; and

a first source and a first drain disposed on two sides of the first semiconductor layer and the etch stopping layer, wherein the first source and the first drain leave a first area exposed on the upper surface, the first source is composed of a first section, a second section, a third section, a fourth section and a fifth section, the first section is disposed on an upper surface of the upper layer, the second section is disposed on a side surface of the etch stopping layer, the third section is disposed on an upper surface of the first semiconductor layer, the fourth section is disposed on a side surface of the first semiconductor layer, and the fifth section is disposed on an upper surface of the first dielectric layer;

wherein the switching transistor comprises;

a second gate;

a second dielectric layer disposed on the second gate;

a second semiconductor layer disposed on the second dielectric layer and patterned into a channel structure above the second gate; and

a second source and a second drain disposed on two sides of the second semiconductor layer, wherein the second source and the second drain leave a second area exposed on the second semiconductor layer, the second source is composed of a sixth section, a seventh section and an eighth section, the sixth section is disposed on an upper surface of the second semiconductor layer, the seventh section is disposed on a side surface of the second semiconductor layer, and the eighth section is disposed on an upper surface of the second dielectric layer;

a third dielectric layer is disposed on the driving transistor and the switching transistor covering at least the full first area and the full second area; and

wherein the first semiconductor layer and the second semiconductor layer are made of an oxide semiconductor material.