US 6,211,533 B1 · Solid state imager including TFTs with variably doped contact layer system for reducing TFT leakage current and increasing mobility

Abstract

A TFT structure includes a variably doped contact layer system in order to reduce leakage current characteristics and increase mobility of the TFT. Such TFTs may be utilized in, for example, X-ray imagers or liquid crystal displays. In certain embodiments, the contact layer system is lightly doped adjacent a semiconductor or channel layer, and is more heavily doped adjacent the source/drain electrodes. The variation in doping density of the contact layer system may be performed in a step-like manner, gradually, continuously, or in any other suitable manner. In certain embodiments, the contact layer system may include a single layer which is deposited over an intrinsic semiconductor layer, with the amount of dopant gas being used during the deposition process being adjusted through the deposition of the single layer so as to cause the doping density to vary (increase or decrease) throughout the thickness of the system/layer.

Claims3

Dependent claims

A transistor structure comprising:

a substrate;
a gate electrode in communication with a gate address line;
a drain electrode in communication with a drain address line;
a source electrode in communication with a device electrode;
a channel defined between said source and drain electrodes;
and
a variably doped contact layer system variably doped throughout its thickness, said variably doped contact layer system being located at least between said drain electrode and a semiconductor layer.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application

09/229,317Filed 13 Jan 1999 · continuation

Priority

15 May 1998

Granted

3 Apr 2001

Term ends

Not estimatedThe source records don’t support an estimate.

Classification8 codes

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 30/0316
Characterised by the gate electrodes: of lateral bottom-gate TFTs comprising only a single gate
H10D 30/0321
Of thin-film transistors [TFT]: comprising silicon, e.g. amorphous silicon or polysilicon
H10D 30/6713
Having supplementary regions or layers in the thin films or in the insulated bulk substrates for controlling properties of the device:…

Solid state imager including TFTs with variably doped contact layer system for reducing TFT leakage current and increasing mobility

Life of this patent

Solid state imager including TFTs with variably doped contact layer system for reducing TFT leakage current and increasing mobility

Life of this patent

Abstract

Claims3