US 2003/0194838 A1 · Transistor and associated driving device

Abstract

A method of forming a thin film transistor and its associated driver. A polysilicon layer, a gate oxide layer and a gate layer are formed on a substrate. A photoresist layer comprising of a top section and a base section is formed over the gate layer. The top section of the photoresist layer patterns out a thin film transistor gate while the base section outside the top section patterns out a lightly doped region or undoped region on each side of the gate. Complementary metal-oxide-semiconductor drivers are formed on each side of the thin film transistor.

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Drawings

Claims21

Dependent claims

A method of forming a thin film transistor, comprising:

providing a substrate;
sequentially forming a polysilicon layer, a gate oxide layer and a gate layer over the substrate;
forming a photoresist layer over the gate layer, wherein the photoresist layer includes a base section and a top section with a width of the base section being greater than a width of the top section;
removing a portion of the gate layer to expose the gate oxide layer while using the photoresist layer as a mask;
conducting an ion implantation to form a first doped region in the polysilicon layer while using the photoresist layer as a mask;
removing a portion of the photoresist layer such that photoresist material in the base section and outside the top section is completely removed, exposing the gate layer underneath and removing a pre-defined thickness of photoresist material from the top section;
removing the exposed gate layer to form a gate electrode;
and
forming an undoped region on each side of the gate electrode.

6 more elements

A method of forming a thin film transistor and its associated driver, comprising:

providing a substrate, wherein the substrate is divided into a first type thin film transistor region, a second type thin film transistor region and a pixel thin film transistor region;
forming a patterned polysilicon layer over the substrate;
sequentially forming a gate oxide layer and a gate layer over the patterned polysilicon layer and the substrate;
forming a patterned first photoresist layer over the first type thin film transistor region, the second type thin film transistor region and the pixel thin film transistor region;
removing a portion of the gate layer to form a first type thin film transistor gate while using the first photoresist layer as a mask;
conducting a first ion implantation to form a first doped region in the polysilicon layer on each side of the first type thin film transistor gate;
removing the first photoresist layer;
forming a patterned second photoresist layer over the second type thin film transistor region, the pixel thin film transistor region and the first type thin film transistor region, wherein the second photoresist layer over the pixel thin film transistor region includes a top section and a base section with a width of the base section being greater than a width of the top section;
removing a portion of the gate layer to expose the gate oxide layer while using the second photoresist layer as a mask;
conducting a second ion implantation to form a second doped region in the polysilicon layer using the second photoresist layer as a mask;
removing a portion of the second photoresist layer such that photoresist material in the base section outside the top section is completely removed, exposing the gate layer underneath and removing a pre-defined thickness of photoresist material from the top section;
and
removing the exposed gate layer to form a pixel thin film transistor gate electrode.

10 more elements

A method of forming a thin film transistor and its associated driver, comprising:

providing a substrate, wherein the substrate is divided into a first type thin film transistor region, a second type thin film transistor region and a pixel thin film transistor region;
forming a patterned polysilicon layer over the substrate;
sequentially forming a gate oxide layer and a gate layer over the patterned polysilicon layer and the substrate;
forming a patterned first photoresist layer over the second type thin film transistor region, the pixel thin film transistor region and the first type thin film transistor region, wherein the first photoresist layer over the pixel thin film transistor region includes a top section and a base section with a width of the base section being greater than a width of the top section;
removing a portion of the gate layer to expose the gate oxide layer while using the first photoresist layer as a mask;
conducting a first ion implantation to form a first doped region in the polysilicon layer while using the first photoresist layer as a mask;
removing a portion of the first photoresist layer such that photoresist material in the base section outside the top section is completely removed, exposing the gate layer underneath and a pre-defined thickness of photoresist material is removed from the top section;
removing the exposed gate layer to form a pixel thin film transistor gate electrode;
removing the first photoresist layer;
forming a patterned second photoresist layer over the first type thin film transistor region, the second type thin film transistor region and the pixel thin film transistor region;
removing a portion of the gate layer to form a first type thin film transistor gate using the second photoresist layer as a mask;
and
conducting a second ion implantation to form a second doped region on each side of the first type thin film transistor gate.

10 more elements

Dependencies are inferred from the claim text.

Description3,923 words

Summary1,440 words

#This application claims the priority benefit of Taiwan application serial no. 90110253, filed on Apr. 30, 2001.

#1. Field of Invention

#The present invention relates to a method of manufacturing a thin film transistor and associated driving device. More particularly, the present invention relates to a method of manufacturing a thin film transistor and associated driving device by forming a photoresist layer having a base section and a top section. The top section patterns out thin film transistor's gate while the base section patterns out a lightly doped drain (LDD) or undoped region so that one less masking step is required.

Brief description of the drawings6 figures

#The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,

#FIGS. 1A through 1C are schematic cross-sectional views showing the steps for producing a conventional thin film transistor with lightly doped drain regions;

#FIGS. 2A through 2C are schematic cross-sectional views showing the steps for fabricating a conventional thin film transistor with lightly doped structures and its associated driver,

Detailed description2,264 words

#Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

#FIGS. 3A through 3C are schematic cross-sectional views showing the steps for producing a thin film transistor with lightly doped drain regions according to one preferred embodiment of this invention. As shown in FIG. 3A, an insulating substrate 300 is provided. A polysilicon layer 302, a gate oxide layer 304 and a gate layer 306a are sequentially formed over the insulating substrate 300. A patterned photoresist layer 308 having a top section 308a and a base section 308b is formed over the gate layer 306a. The patterned photoresist layer 308 later serves as a mask for forming a gate electrode 306b (shown in FIG. 3B) and a lightly doped drain region 312 (shown in FIG. 3C). The base section 308b of the photoresist layer 308 has a width greater than the top section 308a of the photoresist layer 308. The top section 308a of the photoresist layer 308 patterns out the gate electrode 306b (shown in FIG. 3B). The base section 308b outside the top section 308a patterns out the lightly doped drain regions 312 (shown in FIG. 3C).

#A portion of the gate layer 306a is removed using the patterned photoresist layer 308 as a mask. A heavy implantation 314 is next carried out to form heavily doped regions 310 in the polysilicon layer 302. The heavily doped regions 310 can be heavily doped n-type regions, for example.

Facts

Application

10/393,803Filed 20 Mar 2003

Priority

TW 9011025330 Apr 2001

Published

16 Oct 2003

Term ends

Not estimatedThe source records don’t support an estimate.

Classification7 codes

H10D 86/0231
Of multiple TFTs: using masks, e.g. half-tone masks
H10D 30/6715
Characterised by the properties of the source or drain regions, e.g. compositions or sectional shapes: characterised by the doping profiles, e.g.…
H10D 86/40
Integrated devices formed in or on insulating or conducting substrates, e.g. formed in silicon-on-insulator [SOI] substrates or on stainless…
H10D 86/60
Characterised by multiple TFTs: wherein the TFTs are in active matrices

Transistor and associated driving device

Life of this patent

Transistor and associated driving device

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims21

Description3,923 words

Drawings

Classification7 codes

Life of this patent

Description3,923 words