US 6,461,899 B1 · Oxynitride laminate “blocking layer” for thin film semiconductor devices

Abstract

Channel doping is an effective method for controlling Vth, but if Vth shifts to the order of −4 to −3 V when forming circuits such as a CMOS circuit formed from both an n-channel TFT and a P-channel TFT on the same substrate, then it is difficult to control the Vth of both TFTs with one channel dope. In order to solve the above problem, the present invention forms a blocking layer on the back channel side, which is a laminate of a silicon oxynitride film (A) manufactured from SiH4, NH3, and N2O, and a silicon oxynitride film (B)manufactured from SiH4and N2O. By making this silicon oxynitride film laminate structure, contamination by alkaline metallic elements from the substrate can be prevented, and influence by stresses, caused by internal stress, imparted to the TFT can be relieved.

Claims39

Dependent claims

A semiconductor device including at least one thin film transistor formed over a substrate, said semiconductor device comprising:

a first silicon oxynitride film (A) formed on said substrate;
a second silicon oxynitride film (B) formed on said silicon oxynitride film (A);
and
a semiconductor layer formed on the silicon oxynitride film (B),
wherein a composition ratio of nitrogen, with respect to oxygen, in the silicon oxynitride film (A) is more than or equal to 0.6, and is less than or equal to 1.5;
and
a composition ratio of nitrogen, with respect to oxygen, in the silicon oxynitride film (B) is more than or equal to 0.01, and is less than or equal to 0.4.

4 more elements

A semiconductor device having a pixel TFT formed over a pixel portion of a substrate, and an n-type TFT and a p-type TFT of a driver circuit formed over said substrate, comprising:

a first silicon oxynitride film (A) formed on the substrate;
a second silicon oxynitride film (B) formed on the silicon oxynitride film (A);
the pixel TFT formed on the silicon oxynitride film (B), and
the n-type TFT and p-type TFT of the driver circuit;
wherein an oxygen concentration of the silicon oxynitride film(A) is more than or equal to 20 atomic %, and less than or equal to 30 atomic %;
a nitrogen concentration of the silicon oxynitride film (A) is more than or equal to 20 atomic %, and less than or equal to 30 atomic %;
an oxygen concentration of the silicon oxynitride film (B) is more than or equal to 55 atomic %, and less than or equal to 65 atomic %;
and
a nitrogen concentration of the silicon oxynitride film (B) is more than or equal to 1 atomic %, and less than or equal to 20 atomic %.

6 more elements

A method of manufacturing a semiconductor device having a pixel TFT formed over a pixel portion of a substrate, and an n-channel TFT and a p-channel TFT of a driver circuit formed over said substrate, said method comprising the steps of:

forming a silicon oxynitride film (A) on the substrate;
forming a silicon oxynitride film (B) on the silicon oxynitride film (A);
and
forming the pixel TFT, and the n-channel TFT and the P-channel TFT of the driver circuit, on the silicon oxynitride film (B);
wherein a composition ratio of nitrogen, with respect to oxygen, in the silicon oxynitride film (A) is more than or equal to 0.6, and at less than or equal to 1.5;
and
a composition ratio of nitrogen, with respect to oxygen, in the silicon oxynitride film (B) is more than or equal to 0.01, and at less than or equal to 0.4.

4 more elements

forming a silicon oxynitride film (A) on the substrate;
forming a silicon oxynitride film (B) on the silicon oxynitride film (A);
forming the pixel TFT, and the n-channel TFT and the P-channel TFT of the driver circuit, on the silicon oxynitride film (B);
wherein:
the oxygen concentration of the silicon oxynitride film (A) is more than or equal to 20 atomic %, and at less than or equal to 30 atomic %;
the nitrogen concentration of the silicon oxynitride film (A) is more than or equal to 20 atomic %, and at less than or equal to 30 atomic %;
the oxygen concentration of the silicon oxynitride film (B) is more than or equal to 55 atomic %, and at less than or equal to 65 atomic %;
and
the nitrogen concentration of the silicon oxynitride film (B) is more than or equal to 1 atomic %, and at less than or equal to 20 atomic %.

6 more elements

Dependencies are inferred from the claim text.

Oxynitride laminate “blocking layer” for thin film semiconductor devices

Life of this patent

Oxynitride laminate “blocking layer” for thin film semiconductor devices

Life of this patent

Abstract

Claims39