Title of Invention	"A METHOD OF DEPOSITING THIN FILM OF NON METALS"
Abstract	This invention relates to a method of depositing thin film of non metals that is diamond like carbon on any substrate as herein described characterized by the step of forming dense plasma under an inert gas wherein inert gas is argon within the plasma chamber having a copper anode and a set of cathodes assembly a capacitor to provide voltage, focusing the dense plasma on non-metal pellet supported on anode, positioning a holder to hold any substrate away from the anode within the chamber wherein the distance between the anode and the substrate depend on the quality and thickness of film, heating the substrate, focusing of the said dense plasma to allow discharge of the pellet ions to the substrate and to form a film thereon.

Title of Invention

"A METHOD OF DEPOSITING THIN FILM OF NON METALS"

Abstract

This invention relates to a method of depositing thin film of non metals that is diamond like carbon on any substrate as herein described characterized by the step of forming dense plasma under an inert gas wherein inert gas is argon within the plasma chamber having a copper anode and a set of cathodes assembly a capacitor to provide voltage, focusing the dense plasma on non-metal pellet supported on anode, positioning a holder to hold any substrate away from the anode within the chamber wherein the distance between the anode and the substrate depend on the quality and thickness of film, heating the substrate, focusing of the said dense plasma to allow discharge of the pellet ions to the substrate and to form a film thereon.

Full Text	FIELD OE INVENTION This invention relates to a method of depositing thin film of non metals such as diamond like carbon on substrates. BACKGROUND oF INVENTION It. is known that diamond like carbon -films are niet.aet.abJ. e aniporphoua material si- which may include s micro crystalline phase. Such & material has several distinct advantages in that it possesses extreme hardness in the range o-f 1000—3000 kg/mn2 with a generally low -friction coefficient between 0.01 to 0.28. Further. diamond like carbon films have high optical transparency and high electricalrestivity. PRIOR ART It is known to deposit thin films o-f diamond like carbon by the mesthcid of chemical vapour deposition. In one such known method employing hot wire chemical vapour deposition, the disadvantage is that of high substrate temperaturess such as 106K and low deposition rates. Such & process has limited applications. Yet another method known in the art. consists in an electron assisted chemical vapour de-position. Such a method is al&o attended with the di sadvantaae at a hi ah substrate temperature of 106K during deposition. and further it is difficult to control the growth rate. Yet. another disi-idvantacie is the low quality of -films. and consequentially it had limited applications. A plasma assisted chemical vapour deposition method is also known in the art, and which could either be microwave or remote plasma assisted chemical vapour deposition. In the microwave chemical vapour deposition. the substrate is normally Si and which requires to be scratched by SiC. A disadvantage is that of high substrate temperatures in the vicinity of 900°C and low deposition rates. Vet another disadvantage is that its rough surface topoqraphv limits its aptical and electronic. application. In the remote- plasma asisi sited chemical vapour deposition,, the substrates are normally Si and Ni. The di sadvantacie.s are of high substrate temperature, low deposition rate and rough surface topography. A physical vapour deposition method is known in the art. and employing ion beam sputtering with a current, density of source of IMA/Cm2 at 1000 e V. A disadvantage of such a method is that of low cits-position rates and also requires extremely .low pressures. and which adds- to the coats. It is also known in the- art to employ a dual ion sputtering beam, and wherein the substrate can be Si. and variety of metals. A disadvantage of such a method is that the deposition rate laser depends an pressure. OBJECTS OF THE PRESENT INVENTION An object. of the present, invention is to propose & process far depositing thin films of metals and nan metals such as diamond like carbon -films. Another object of this invention ie to propose a process for depositing thin -films of metals; and non metals such as diamond like carbon films which obviate the disadvantages of the prior art. Vet another obiect of this invention is to propose a process -for depositing thin films of metals and non metals such as diamond like carbon films which has high deposition rates. Still another obiect of this invention is to propose a process far depasiting thin -Films of metals and non metals such as diamond like carbon films which having smooth surface topography. A further object of this invention is to propose a process for depositing thin films of metals and non metals such as diamond like carbon films which has the required optical transparency. A still further object of this invention is to propose a process for depositing thin films of metals and non metals such as diamond like carbon films which have required structural, optical including IR and UV range, mechanical and electronic properties. Yet a further object of this invention is to propose a process for depositing thin films of metals and non metals such as diamond like carbon films which has a high electrical restivity. Another object of this invention is to propose a process for depositing thin films of metals and non metals such as diamond like carbon films on different substrates. DESCRIPTION OF INVENTION According to this invention there is provided a method of depositing thin film of non metals that is diamond like carbon on any substrate as herein described characterized by the step of forming dense plasma under an inert gas wherein inert gas is argon within the plasma chamber having a copper anode and a set of cathodes assembly a capacitor to provide voltage, focusing the dense plasma on non-metal pellet supported on anode, positioning a holder to hold any substrate away from the anode wherein the distance between the anode and the substrate depend on the quality and thickness of film.within the chamber, heating the substrate, focusing of the said dense plasma to allow discharge of the pellet ions to the substrate and to form a film thereon. DESCRIPTION OF THE INVENTION WITH REFERENCE TO ACCOMPANYING DRAWING Reference is made to fig. 1 which illustrates an apparatus that can be employed for carrying out the process of the present invention. However, it is to be understood that the apparatus of fig. 1 is only exemplary in nature as any other apparatus may be employed. Reference to fig. 1, the device 1 that may as by way of example be employed in the process of the present invention comprises a focus chamber 2 made of mild steel or stainless steel and has an insulator sleeve 3 which assists in the formation of the plasma. A high voltage charger 4 is connected to a capacitor C1. which charges capacitor C1. A spark gap SG allows a discharge from capacitor C1 to an electrode assembly consistino of a centrally disposed anode made up of copper and -filed with graphite 5 and a set. of symmetrically disposed cathodes 7. A voltage of 12-17 KV is applied to capacitor C1 ,. Thus, when capacitor C1 discharges a plasma sheet is -formed between anode 5 and backwall plate 8 and connected to cathodes 7, The height o-f insulator sleeve 3 determines the shape o-f plasma sheet. The plasma is -formed in an atmosphere of an inert, etas, such as argon. The plasma temperature is 0.5 Key to 10 Kev. and pre-ferabl y between 1 Key to 5 Kev. The plasma density is 1022 m -3 to 1027 m -3 and preferablv 1024m-3 to 1027 m-3 Due to the maanetic -field there is a -force which moves the plasma sheet away -from anode 5 and when it reaches cathodes 7. the radial component of current densitv and azimuthal magnetic, -field gives an axial force so that the plasma sheet moves at a high speed upwards.. and when it reaches the top o-f anode 5. there is an axial component o-f current density and azimuthal magnetic -field. but. as current. is in the opposite direction, it results in a collapsing of- plasma radially inward w2th such a compression, a high temperature and density plasma acts on the graphite 12 supported at the top of anode 5 and allows the release of ions in a conical shower towardss the substrate 5.0. artel with the shutter in a withdrawn position. in accordance with this invention, a heater is provided at the holding end of a brass- holder 11 for holdinq substrate10, The ion flux used in the process is 1015to 1020 ion/blast, and preferably 1010 to 1018 10ns/blast. the ion energy is- 1 Kev to 10 may. The device has a vacuun pump lo with a pressure qande 14. Further. & pas inlet 15 is- provided with device 1 far introduction of a gas. such as around. in operation, device 1 is first evacuated by vacuum pump .13. Arpan gas is then introduced through gas iniet 15. Holder 11 can be moved along the vertical axis sO a si to allow the; distance of aubatrate J.0 to be varied from anode 5. Dependina on the quality and thickness of film. substrate 1(3 is diapoaed at a distance of 1 to 10 cm from anode 5. In accordance! with this invention the substate 3. s heated to a temper ature of ambient to 500oc, and prefer abaly 100 to 3000C. the pellet has a thickness of 5 mm to i cm. WE CLAIM; 1. A method of depositing thin film of non metals that is diamond like carbon on any substrate as herein described characterized by the step of forming dense plasma under an inert gas wherein inert gas is argon within the plasma chamber having a copper anode and a set of cathodes assembly a capacitor to provide voltage, focusing the dense plasma on non-metal pellet supported on anode, positioning a holder to hold any substrate away from the anode within the chamber wherein the distance between the anode and the substrate depend on the quality and thickness of film, heating the substrate, focusing of the said dense plasma to allow discharge of the pellet ions to the substrate and to form a film thereon. 2. A method as claimed in claim 1 wherein said pellet is a graphite pellet. 3. A method as claimed in claim 1 wherein the temperature of the substrate is within 500°C. and preferably 100 to 300°C. 4. A method as claimed in claim 1 wherein the plasma density is 1022 nr3 to 1027 m-3 and preferably 1024 nr3 to 1027 rrr3. 6. A method as claimed in claim 1 wherein the plasma temperature is 0.5 to 10 kev. And preferably 1 kev to 5 kwv. 7. A method as claimed in claim 1 wherein the thickness of the pellet is 5mm to 1 cm. 8. A method as claimed in claim 1 wherein voltage of 12-17 KV is applied to the capacitor. 9. A method of depositing thin films of non metals that is diamond like carbon on a substrate substantially as herein described.

Full Text

FIELD OE INVENTION
This invention relates to a method of depositing thin film of non metals such as
diamond like carbon on substrates.
BACKGROUND oF INVENTION
It. is known that diamond like carbon -films are niet.aet.abJ. e aniporphoua material si- which may include s micro crystalline phase. Such & material has several distinct advantages in that it possesses extreme hardness in the range o-f 1000—3000 kg/mn2 with a generally low -friction coefficient between 0.01 to 0.28. Further. diamond like carbon films have high optical transparency and high electricalrestivity.
PRIOR ART
It is known to deposit thin films o-f diamond
like carbon by the mesthcid of chemical vapour
deposition. In one such known method employing hot wire
chemical vapour deposition, the disadvantage is that of
high substrate temperaturess such as 106K and low
deposition rates. Such & process has limited
applications.

Yet another method known in the art. consists in an electron assisted chemical vapour de-position. Such a method is al&o attended with the di sadvantaae at a hi ah substrate temperature of 106K during deposition. and further it is difficult to control the growth rate. Yet. another disi-idvantacie is the low quality of -films. and consequentially it had limited applications.
A plasma assisted chemical vapour deposition method is also known in the art, and which could either be microwave or remote plasma assisted chemical vapour deposition. In the microwave chemical vapour deposition. the substrate is normally Si and which requires to be scratched by SiC. A disadvantage is that of high substrate temperatures in the vicinity of 900°C and low deposition rates. Vet another disadvantage is that its rough surface topoqraphv limits its aptical and electronic. application. In the remote- plasma asisi sited chemical vapour deposition,, the substrates are normally Si and Ni. The di sadvantacie.s are of high substrate temperature, low deposition rate and rough surface topography.
A physical vapour deposition method is known in the art. and employing ion beam sputtering with a

current, density of source of IMA/Cm2 at 1000 e V. A disadvantage of such a method is that of low cits-position rates and also requires extremely .low pressures. and which adds- to the coats.
It is also known in the- art to employ a dual ion sputtering beam, and wherein the substrate can be Si. and variety of metals. A disadvantage of such a method is that the deposition rate laser depends an pressure.
OBJECTS OF THE PRESENT INVENTION
An object. of the present, invention is to
propose & process far depositing thin films of metals and
nan metals such as diamond like carbon -films.
Another object of this invention ie to
propose a process for depositing thin -films of metals;
and non metals such as diamond like carbon films which
obviate the disadvantages of the prior art.
Vet another obiect of this invention is to
propose a process -for depositing thin films of metals
and non metals such as diamond like carbon films which
has high deposition rates.
Still another obiect of this invention is to
propose a process far depasiting thin -Films of metals
and non metals such as diamond like carbon films which
having smooth surface topography.

A further object of this invention is to propose a process for depositing thin films of metals and non metals such as diamond like carbon films which has the required optical transparency.
A still further object of this invention is to propose a process for depositing thin films of metals and non metals such as diamond like carbon films which have required structural, optical including IR and UV range, mechanical and electronic properties.
Yet a further object of this invention is to propose a process for depositing thin films of metals and non metals such as diamond like carbon films which has a high electrical restivity.
Another object of this invention is to propose a process for depositing thin films of metals and non metals such as diamond like carbon films on different substrates.
DESCRIPTION OF INVENTION
According to this invention there is provided a method of depositing thin film of non metals that is diamond like carbon on any substrate as herein described characterized by the step of forming dense plasma under an inert gas wherein inert gas is argon within the plasma chamber having a copper anode and a set of cathodes assembly a capacitor to provide voltage, focusing the dense plasma on non-metal pellet supported on

anode, positioning a holder to hold any substrate away from the anode wherein the distance between the anode and the substrate depend on the quality and thickness of film.within the chamber, heating the substrate, focusing of the said dense plasma to allow discharge of the pellet ions to the substrate and to form a film thereon.
DESCRIPTION OF THE INVENTION WITH REFERENCE TO ACCOMPANYING DRAWING
Reference is made to fig. 1 which illustrates an apparatus that can be employed for carrying out the process of the present invention. However, it is to be understood that the apparatus of fig. 1 is only exemplary in nature as any other apparatus may be employed.
Reference to fig. 1, the device 1 that may as by way of example be employed in the process of the present invention comprises a focus chamber 2 made of mild steel or stainless steel and has an insulator sleeve 3 which assists in the formation of the plasma. A high voltage charger 4 is connected to a capacitor C1. which charges capacitor C1. A spark gap SG allows a discharge from capacitor C1 to an electrode assembly

consistino of a centrally disposed anode made up of copper and -filed with graphite 5 and a set. of symmetrically disposed cathodes 7. A voltage of 12-17 KV is applied to capacitor C1 ,. Thus, when capacitor C1 discharges a plasma sheet is -formed between anode 5 and backwall plate 8 and connected to cathodes 7, The height o-f insulator sleeve 3 determines the shape o-f plasma sheet.
The plasma is -formed in an atmosphere of an inert, etas, such as argon. The plasma temperature is 0.5 Key to 10 Kev. and pre-ferabl y between 1 Key to 5 Kev.
The plasma density is 1022 m -3 to 1027 m -3 and preferablv 1024m-3 to 1027 m-3
Due to the maanetic -field there is a -force which moves the plasma sheet away -from anode 5 and when it reaches cathodes 7. the radial component of current densitv and azimuthal magnetic, -field gives an axial force so that the plasma sheet moves at a high speed upwards.. and when it reaches the top o-f anode 5. there is an axial component o-f current density and azimuthal magnetic -field. but. as current. is in the opposite direction, it results in a collapsing of- plasma radially inward w2th such a compression, a high temperature and density plasma acts on the graphite 12 supported at the

top of anode 5 and allows the release of ions in a conical shower towardss the substrate 5.0. artel with the shutter in a withdrawn position. in accordance with this invention, a heater is provided at the holding end of a brass- holder 11 for holdinq substrate10,
The ion flux used in the process is 1015to
1020 ion/blast, and preferably 1010 to 1018 10ns/blast. the ion energy is- 1 Kev to 10 may.
The device has a vacuun pump lo with a pressure qande 14. Further. & pas inlet 15 is- provided with device 1 far introduction of a gas. such as around.
in operation, device 1 is first evacuated by vacuum pump .13. Arpan gas is then introduced through gas iniet 15.
Holder 11 can be moved along the vertical axis sO a si to allow the; distance of aubatrate J.0 to be varied from anode 5. Dependina on the quality and thickness of film. substrate 1(3 is diapoaed at a distance of 1 to 10 cm from anode 5.
In accordance! with this invention the substate 3. s heated to a temper ature of ambient to 500oc, and prefer abaly 100 to 3000C. the pellet has a thickness of 5 mm to i cm.

WE CLAIM;
1. A method of depositing thin film of non metals that is diamond like carbon on any substrate as herein described characterized by the step of forming dense plasma under an inert gas wherein inert gas is argon within the plasma chamber having a copper anode and a set of cathodes assembly a capacitor to provide voltage, focusing the dense plasma on non-metal pellet supported on anode, positioning a holder to hold any substrate away from the anode within the chamber wherein the distance between the anode and the substrate depend on the quality and thickness of film, heating the substrate, focusing of the said dense plasma to allow discharge of the pellet ions to the substrate and to form a film thereon.
2. A method as claimed in claim 1 wherein said pellet is a graphite pellet.
3. A method as claimed in claim 1 wherein the temperature of the
substrate is within 500°C. and preferably 100 to 300°C.
4. A method as claimed in claim 1 wherein the plasma density is 1022 nr3
to 1027 m-3 and preferably 1024 nr3 to 1027 rrr3.

6. A method as claimed in claim 1 wherein the plasma temperature is
0.5 to 10 kev. And preferably 1 kev to 5 kwv.
7. A method as claimed in claim 1 wherein the thickness of the pellet is
5mm to 1 cm.
8. A method as claimed in claim 1 wherein voltage of 12-17 KV is
applied to the capacitor.
9. A method of depositing thin films of non metals that is diamond like
carbon on a substrate substantially as herein described.

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Patent Number

218110

Indian Patent Application Number

3361/DEL/1998

PG Journal Number

19/2008

Publication Date

09-May-2008

Grant Date

31-Mar-2008

Date of Filing

11-Nov-1998

Name of Patentee

SAVITA ROY

Applicant Address

DEPARTMENT OF PHYSICS AND ASTROPHYSICS, UNIVERSITY OF DELHI, DELHI-110 007

Inventors:

#	Inventor's Name	Inventor's Address
1	MAHESH PRASAD SRIVASTAVA	DEPARTMENT OF PHYSICS AND ASTROPHYSICS, UNIVERSITY OF DELHI, DELHI-110 007, INDIA.
2	SAVITA ROY	DEPARTMENT OF PHYSICS AND ASTROPHYSICS, UNIVERSITY OF DELHI, DELHI-110 007
3	RAVI KANT CHHAYA	DEPARTMENT OF PHYSICS AND ASTROPHYSICS, UNIVERSITY OF DELHI, DELHI-110 007

PCT International Classification Number

B05D 1/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA