US6794255B1 Expired / Lapsed US ⏱️ 0.0 years remaining

Carburized silicon gate insulators for integrated circuits

Assignee: Mosaid Technologies Inc

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Filing: 1999-02-26

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Granted: 2004-09-21

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Expires: 2019-02-26

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Abstract

Abstract Silicon carbide films are grown by carburization of silicon to form insulative films. In one embodiment, the film is used to provide a gate insulator for a field effect transistor. The film is grown in a microwave-plasma-enhanced chemical vapor deposition (MPECVD) system. A silicon substrate is fast etched in dilute HF solution and rinsed. The substrate is then placed in a reactor chamber of the MPECVD system in hydrogen along with a carbon containing gas. The substrate is then inserted into a microwave generated plasma for a desired time to grow the film. The microwave power varies depending on substrate size. The growth of the film may be continued following formation of an initial film via the above process by using a standard CVD deposition of amorphous SiC. The film may be used to form gate insulators for FET transistors in DRAM devices and flash type memories. It may be formed as dielectric layers in capacitors in the same manner.

Inventors

👤 Leonard Forbes
👤 Kie Y. Ahn

Bibliographic Details

Application Number —

Jurisdiction US

Data Source google_patents

Last Synchronized 2026-11-09 01:25

CPC Classifications

G; G11; G11C; G11C16/00; G11C16/02; G11C16/04; G11C16/0466; H; H10; H10B; H10B12/00; H10B12/01; H10B12/02; H10B12/03; H10B12/033; H10D; H10D30/00; H10D30/60; H10D30/68; H10D30/6891; H10D30/69; H10D30/694; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01332; H10D64/01336; H10D64/01342; H10D64/031; H10D64/035; H10D64/20; H10D64/27; H10D64/311; H10D64/411; H10D64/511; H10D64/514; H10D64/60; H10D64/66; H10D64/68; H10D1/00; H10D1/60; H10D1/68; Y; Y10; Y10S; Y10S438/00; Y10S438/931

Claims Analysis

Total Claims: 29

Claim 1

Independent Claim 60 words

A method of forming a semiconductor device comprising: cleaning a silicon substrate; growing a layer of amorphous SiC on and contacting the silicon substrate in a microwave-plasma-enhanced chemical vapor deposition chamber in a hydrocarbon containing gas; forming a gate over and contacting the layer of amorphous SiC; and forming a source region and a drain region in the silicon substrate.

Claim 2

Independent Claim 60 words

Claim 3

Dependent Claim 179 words

The method of claim 1 wherein: cleaning a silicon substrate comprises etching a p− silicon substrate in a dilute HF for about one minute and then rinsing the silicon substrate in deionized water; growing a layer of amorphous SiC comprises: evacuating a microwave-plasma-enhanced chemical vapor deposition chamber to a pressure of approximately 10−4 or 10−5 mTorr; inserting the silicon substrate into the chamber at a temperature of approximately 400 to 500 degrees C.; raising the temperature of the chamber to approximately 915 to 1250 degrees C.; applying an electrical bias of between approximately zero and 200 volts; growing a first layer of amorphous SiC on the silicon substrate in the chamber in a gas comprising hydrogen and approximately 2% to 10% methane at a pressure of approximately 15 to 25 Torr and a microwave power of between approximately 250 and 1000 watts; forming a source region comprises forming an n+ drain region and an n+ source region in the silicon substrate; and further comprising forming additional amorphous SiC on the first layer of amorphous SiC by chemical vapor deposition.

Claim 4

Dependent Claim 15 words

The method of claim 1 , wherein forming a semiconductor device includes forming a memory.

Claim 5

Dependent Claim 16 words

The method of claim 1 , wherein forming a semiconductor device includes forming an imaging device.

Claim 6

Independent Claim 70 words

A method of forming a semiconductor device comprising: growing a layer of amorphous SiC on and contacting a silicon substrate in a microwave-plasma-enhanced chemical vapor deposition chamber in a hydrogen and hydrocarbon gas which contains from about 1 to 10 carbon atoms per molecule; forming a gate on top of and contacting the layer of amorphous SiC; and forming a source region and a drain region in the silicon substrate.

Claim 7

Independent Claim 70 words

Claim 8

Dependent Claim 36 words

The method of claim 5 wherein growing a layer of amorphous SiC further comprises growing the layer of amorphous SiC in a gas comprising hydrogen and at least one of methane, ethane, ethylene, acetylene, and ethanol.

Claim 9

Dependent Claim 35 words

The method of claim 5 wherein growing a layer of amorphous SiC further comprises growing the layer of amorphous SiC in a gas comprising hydrogen and an approximately 2% to 10% concentration of hydrocarbon gas.

Claim 10

Dependent Claim 31 words

The method of claim 5 wherein growing a first layer of amorphous SiC further comprises growing the layer of amorphous SiC in a pressure of between approximately 15 to 25 Torr.

Claim 11

Dependent Claim 56 words

The method of claim 5 wherein growing a layer of amorphous SiC includes forming a first amorphous SiC layer and a second amorphous SiC layer, forming a second amorphous SiC layer on the first layer of amorphous SiC by chemical vapor deposition of amorphous SiC after growing the first layer and prior to forming the gate.

Claim 12

Dependent Claim 31 words

The method of claim 5 wherein growing a layer of amorphous SiC further comprises growing the layer of amorphous SiC at a microwave power of between approximately 250 to 1000 watts.

Claim 13

Dependent Claim 183 words

The method of claim 5 wherein: growing a layer of amorphous SiC comprises: evacuating a microwave-plasma-enhanced chemical vapor deposition chamber to a pressure of approximately 10−4 or 10−5 mTorr; inserting a p− silicon substrate into the chamber at a temperature of approximately 400 to 500 degrees C.; raising the temperature of the chamber to approximately 915 to 1250 degrees C.; applying an electrical bias of between approximately zero and 200 volts; growing a first layer of amorphous SiC on the silicon substrate in the chamber in a gas comprising hydrogen and approximately 2% to 10% methane at a pressure of approximately 15 to 25 Torr and a microwave power of between approximately 250 and 1000 watts; forming a source region comprises forming an n+ drain region and an n+ source region in the silicon substrate; and further comprising: etching the silicon substrate in a dilute HF for about one minute and then rinsing the silicon substrate in deionized water before growing the first layer of amorphous SiC; and forming additional amorphous SiC on the first layer of amorphous SiC by chemical vapor deposition.

Claim 14

Independent Claim 86 words

A method of forming a semiconductor device comprising: growing a layer of amorphous SiC on and contacting a silicon substrate in a microwave-plasma-enhanced chemical vapor deposition chamber in a 2 to 10% concentration of a hydrocarbon gas which contains from about 1 to 10 carbon atoms per molecule in hydrogen at a pressure of between approximately 15 to 25 Torr; forming a gate on top of and contacting the layer of amorphous SiC; and forming a source region and a drain region in the silicon substrate.

Claim 15

Independent Claim 86 words

A method of forming a semiconductor device comprising: growing a layer of amorphous SiC on and contacting a silicon substrate in a microwave-plasma-enhanced chemical vapor deposition chamber in a 2 to 10% concentration of a hydrocarbon gas which contains from about 1 to 10 carbon atoms per molecule in hydrogen at a pressure of between approximately 15 to 25 Torr; forming a gate on top of and contacting the layer of amorphous SiC; and forming a source region and a drain region in the silicon substrate.

Claim 16

Dependent Claim 183 words

The method of claim 12 wherein: growing a layer of amorphous SiC comprises: evacuating a microwave-plasma-enhanced chemical vapor deposition chamber to a pressure of approximately 10−4 or 10−5 mTorr; inserting a p− silicon substrate into the chamber at a temperature of approximately 400 to 500 degrees C.; raising the temperature of the chamber to approximately 915 to 1250 degrees C.; applying an electrical bias of between approximately zero and 200 volts; growing a first layer of amorphous SiC on the silicon substrate in the chamber in a gas comprising hydrogen and approximately 2% to 10% methane at a pressure of approximately 15 to 25 Torr and a microwave power of between approximately 250 and 1000 watts; forming a source region comprises forming an n+ drain region and an n+ source region in the silicon substrate; and further comprising: etching the silicon substrate in a dilute HF for about one minute and then rinsing the silicon substrate in deionized water before growing the first layer of amorphous SiC; and forming additional amorphous SiC on the first layer of amorphous SiC by chemical vapor deposition.

Claim 17

Independent Claim 128 words

A method of forming a semiconductor device comprising: growing a first layer of amorphous SiC on and contacting a silicon substrate in a microwave-plasma-enhanced chemical vapor deposition chamber at a microwave power of between approximately 250 to 1000 watts in a hydrocarbon gas which contains from about 1 to 10 carbon atoms per molecule in hydrogen; forming a gate on top of the first layer of amorphous SiC; forming a source region and a drain region in the silicon substrate; and forming a second amorphous SiC layer on and contacting the first layer of amorphous SiC by chemical vapor deposition of amorphous SiC after growing the first layer of amorphous SiC and prior to forming the gate, wherein the gate is formed contacting the second amorphous SiC layer.

Claim 18

Independent Claim 128 words

Claim 19

Dependent Claim 168 words

The method of claim 14 wherein: growing a first layer of amorphous SiC comprises: evacuating a microwave-plasma-enhanced chemical vapor deposition chamber to a pressure of approximately 10−4 or 10−5 mTorr; inserting a p− silicon substrate into the chamber at a temperature of approximately 400 to 500 degrees C.; raising the temperature of the chamber to approximately 915 to 1250 degrees C.; applying an electrical bias of between approximately zero and 200 volts; growing the first layer of amorphous SiC on the silicon substrate in the chamber in a gas comprising hydrogen and approximately 2% to 10% methane at a pressure of approximately 15 to 25 Torr and a microwave power of between approximately 250 and 1000 watts; forming a source region comprises forming an n+ drain region and an n+ source region in the silicon substrate; and further comprising etching the silicon substrate in a dilute HF for about one minute and then rinsing the silicon substrate in deionized water before growing the first layer of amorphous SiC.

Claim 20

Independent Claim 144 words

A method of forming a semiconductor device comprising: growing a first layer of amorphous SiC on and contacting a silicon substrate in a microwave-plasma-enhanced chemical vapor deposition chamber at a microwave power of between approximately 250 to 1000 watts in a 2 to 10% concentration of a hydrocarbon gas which contains from about 1 to 10 carbon atoms per molecule in hydrogen at a pressure of between approximately 15 to 25 Torr; forming a gate on top of the first layer of amorphous SiC; forming a source region and a drain region in the silicon substrate; and forming a second amorphous SiC layer on and contacting the first layer of amorphous SiC by chemical vapor deposition of amorphous SiC after growing the first layer of amorphous SiC and prior to forming the gate, wherein the Rate is formed contacting the second amorphous SiC layer.

Claim 21

Independent Claim 144 words

A method of forming a semiconductor device comprising: growing a first layer of amorphous SiC on and contacting a silicon substrate in a microwave-plasma-enhanced chemical vapor deposition chamber at a microwave power of between approximately 250 to 1000 watts in a 2 to 10% concentration of a hydrocarbon gas which contains from about 1 to 10 carbon atoms per molecule in hydrogen at a pressure of between approximately 15 to 25 Torr; forming a gate on top of the first layer of amorphous SiC; forming a source region and a drain region in the silicon substrate; and forming a second amorphous SiC layer on and contacting the first layer of amorphous SiC by chemical vapor deposition of amorphous SiC after growing the first layer of amorphous SiC and prior to forming the gate, wherein the Rate is formed contacting the second amorphous SiC layer.

Claim 22

Dependent Claim 168 words

The method of claim 16 wherein: growing a first layer of amorphous SiC comprises: evacuating a microwave-plasma-enhanced chemical vapor deposition chamber to a pressure of approximately 10−4 or 10−5 mTorr; inserting a p− silicon substrate into the chamber at a temperature of approximately 400 to 500 degrees C.; raising the temperature of the chamber to approximately 915 to 1250 degrees C.; applying an electrical bias of between approximately zero and 200 volts; growing the first layer of amorphous SiC on the silicon substrate in the chamber in a gas comprising hydrogen and approximately 2% to 10% methane at a pressure of approximately 15 to 25 Torr and a microwave power of between approximately 250 and 1000 watts; forming a source region comprises forming an n+ drain region and an n+ source region in the silicon substrate; and further comprising etching the silicon substrate in a dilute HF for about one minute and then rinsing the silicon substrate in deionized water before growing the first layer of amorphous SiC.

Claim 23

Independent Claim 105 words

A method of forming a semiconductor device comprising: cleaning a silicon substrate; growing a layer of amorphous SiC directly on the silicon substrate in a microwave-plasma-enhanced chemical vapor deposition chamber in a hydrocarbon containing gas; forming a gate over and contacting the layer of amorphous SiC; forming a source region and a drain region in the silicon substrate; forming a bottom conductive layer on and contacting one of the source region or the drain region; forming a silicon layer on the bottom conductive layer; carburizing the silicon layer to become a second SiC layer; and forming a top conductive layer on the second SiC layer.

Claim 24

Independent Claim 105 words

Claim 25

Dependent Claim 28 words

The method of claim 18 , wherein the method further includes depositing amorphous SiC on the second SiC layer to increase the thickness of the second SiC layer.

Claim 26

Dependent Claim 59 words

The method of claim 18 , wherein carburizing the silicon layer to become a second SiC layer includes carburizing the silicon layer to become the second SiC layer in contact with the bottom conductive layer and forming a top conductive layer on the second SiC layer includes forming the top conductive layer in contact with the second SiC layer.

Claim 27

Dependent Claim 41 words

The method of claim 20 , wherein the method further includes depositing amorphous SiC on the second SiC layer to increase the thickness of the second SiC layer before forming the top conductive layer in contact with the second SiC layer.

Claim 28

Dependent Claim 15 words

The method of claim 18 , wherein forming a semiconductor device includes forming a memory.

Claim 29

Dependent Claim 17 words

The method of claim 22 , wherein forming a memory includes forming a dynamic random access memory.

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USPTO Annuity & Maintenance Windows

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2007-09-21	2008-03-22	2008-09-21	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2011-09-21	2012-03-22	2012-09-21	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2015-09-21	2016-03-22	2016-09-21	$7700.00	Window Closed / Lapsed

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