US5039625A
Expired / Lapsed
US
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Maximum areal density recessed oxide isolation (MADROX) process
Assignee: MCNC Research and Development Institute
•
Filing: 1990-04-27
•
Granted: 1991-08-13
•
Expires: 2010-04-27
Abstract
Abstract A Maximum Areal Density Recessed Oxide Isolation (MADROX) process for forming semiconductor devices, in which forms an insulating layer is formed on a monocrystalline silicon substrate and a patterned polycrystalline silicon-containing layer is formed on the insulating layer. The substrate is then subjected to a low temperature plasma assisted oxidation to form recessed oxide isolation areas in the exposed regions of the substrate, with minimal encroachment under the patterned polycrystalline silicon-containing layer. The patterned polycrystalline silicon-containing layer acts as a mask, without itself being oxidized. Low temperature recessed oxide isolation regions may thereby be formed, without "bird's beak" formation. Maximum Areal Density Bipolar and Field Effect Transistor (MADFET) devices may be formed, using the patterned polycrystalline silicon-containing layer as a device contact if desired.
Inventors
- 👤 Arnold Reisman
- 👤 Mark Kellam
- 👤 Charles K. Williams
- 👤 Nandini Tandon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:43
CPC Classifications
H; H10; H10D; H10D84/00; H10D84/01; H10D84/0123; H10D84/0126; H10D84/0151; H10D84/02; H10D84/03; H10D84/038; H10P; H10P14/00; H10P14/60; H10P14/61; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/012; H10W10/10; H10W10/13; Y; Y10; Y10S; Y10S148/00; Y10S148/086; Y10S148/117
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
120 words
A process for forming maximum areal density recessed oxide (MADROX) isolation regions in a monocrystalline silicon substrate, comprising the steps of: forming an insulating layer on said monocrystalline silicon substrate; and then fabricating a patterned polycrystalline silicon-containing layer on said insulating layer, said patterned polycrystalline silicon-containing layer defining predetermined regions of said monocrystalline silicon substrate; and then performing plasma assisted oxidation on said monocrystalline silicon substrate having the insulating layer and the patterned polycrystalline silicon-containing layer thereon, to thereby form recessed oxide isolation regions in the predetermined regions of said monocrystalline silicon substrate, with minimal encroachment under the patterned polycrystalline silicon-containing layer and with oxidizing the polycrystalline silicon-containing layer on said monocrystalline silicon substrate during the plasma assisted oxidation step.
Claim 2
Dependent Claim
120 words
A process for forming maximum areal density recessed oxide (MADROX) isolation regions in a monocrystalline silicon substrate, comprising the steps of: forming an insulating layer on said monocrystalline silicon substrate; and then fabricating a patterned polycrystalline silicon-containing layer on said insulating layer, said patterned polycrystalline silicon-containing layer defining predetermined regions of said monocrystalline silicon substrate; and then performing plasma assisted oxidation on said monocrystalline silicon substrate having the insulating layer and the patterned polycrystalline silicon-containing layer thereon, to thereby form recessed oxide isolation regions in the predetermined regions of said monocrystalline silicon substrate, with minimal encroachment under the patterned polycrystalline silicon-containing layer and with oxidizing the polycrystalline silicon-containing layer on said monocrystalline silicon substrate during the plasma assisted oxidation step.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein said insulating layer comprises silicon dioxide.
Claim 4
Dependent Claim
12 words
The process of claim 1 wherein said insulating layer is void free.
Claim 5
Dependent Claim
16 words
The process of claim 2 wherein said silicon dioxide layer is at least 7 nm thick.
Claim 6
Dependent Claim
25 words
The process of claim 1 wherein said polycrystalline silicon-containing layer is selected from the group consisting of undoped polycrystalline silicon, doped polycrystalline silicon and polycide.
Claim 7
Dependent Claim
20 words
The process of claim 1 wherein said plasma assisted oxidation is performed at temperatures between 300° C. and 700° C.
Claim 8
Dependent Claim
19 words
The process of claim 1 wherein said plasma assisted oxidation is performed at a temperature of about 500° C.
Claim 9
Dependent Claim
17 words
The process of claim 1 wherein said plasma assisted oxidation comprises radio frequency generated plasma assisted oxidation.
Claim 10
Dependent Claim
26 words
The process of claim 1 wherein said fabricating step is followed by the step of fabricating spacers on the sidewall of said patterned polycrystalline silicon-containing layer.
Claim 11
Dependent Claim
139 words
A process for forming maximum areal density semiconductor devices in a monocrystalline silicon substrate, comprising the steps of: forming an insulating layer on said monocrystalline silicon substrate; and then fabricating a patterned polycrystalline silicon-containing layer on said insulating layer, said patterned polycrystalline silicon-containing layer defining predetermined regions of said monocrystalline silicon substrate; and then performing plasma assisted oxidation on said monocrystalline silicon substrate having the insulating layer and the patterned polycrystalline silicon-containing layer thereon, to thereby form recessed oxide isolation regions in the predetermined regions of said monocrystalline silicon substrate, with minimal encroachment under the patterned polycrystalline silicon-containing layer and without oxidizing the polycrystalline silicon-containing layer on said monocrystalline silicon substrate during said plasma assisted oxidation step; removing said patterned polycrystalline silicon-containing layer; and forming said semiconductor devices in the monocrystalline silicon substrate, between the recessed oxide isolation regions.
Claim 12
Dependent Claim
139 words
A process for forming maximum areal density semiconductor devices in a monocrystalline silicon substrate, comprising the steps of: forming an insulating layer on said monocrystalline silicon substrate; and then fabricating a patterned polycrystalline silicon-containing layer on said insulating layer, said patterned polycrystalline silicon-containing layer defining predetermined regions of said monocrystalline silicon substrate; and then performing plasma assisted oxidation on said monocrystalline silicon substrate having the insulating layer and the patterned polycrystalline silicon-containing layer thereon, to thereby form recessed oxide isolation regions in the predetermined regions of said monocrystalline silicon substrate, with minimal encroachment under the patterned polycrystalline silicon-containing layer and without oxidizing the polycrystalline silicon-containing layer on said monocrystalline silicon substrate during said plasma assisted oxidation step; removing said patterned polycrystalline silicon-containing layer; and forming said semiconductor devices in the monocrystalline silicon substrate, between the recessed oxide isolation regions.
Claim 13
Dependent Claim
12 words
The process of claim 10 wherein said insulating layer comprises silicon dioxide.
Claim 14
Dependent Claim
12 words
The process of claim 10 wherein said insulating layer is void free.
Claim 15
Dependent Claim
16 words
The process of claim 11 wherein said silicon dioxide layer is at least 7 nm thick.
Claim 16
Dependent Claim
25 words
The process of claim 10 wherein said polycrystalline silicon-containing layer is selected from the group consisting of undoped polycrystalline silicon, doped polycrystalline silicon and polycide.
Claim 17
Dependent Claim
20 words
The process of claim 10 wherein said plasma assisted oxidation is performed at temperatures between 300° C. and 700° C.
Claim 18
Dependent Claim
19 words
The process of claim 10 wherein said plasma assisted oxidation is performed at a temperature of about 500° C..
Claim 19
Dependent Claim
17 words
The process of claim 10 wherein said plasma assisted oxidation comprises radio frequency generated plasma assisted oxidation.
Claim 20
Dependent Claim
26 words
The process of claim 10 wherein said fabricating step is followed by the step of fabricating spacers on the sidewall of said patterned polycrystalline silicon-containing layer.
Claim 21
Dependent Claim
29 words
The process of claim 10 wherein said semiconductor device forming step comprises the step of forming bipolar transistors in the monocrystalline silicon substrate, between the recessed oxide isolation regions.
Claim 22
Dependent Claim
150 words
A process for forming Maximum Areal Density Field Effect Transistor (MADFET) devices in a monocrystalline silicon substrate, comprising the steps of: forming an insulating layer on said monocrystalline silicon substrate; and then fabricating a patterned polycrystalline silicon-containing layer on said insulating layer, said patterned polycrystalline silicon-containing layer defining first predetermined regions of said monocrystalline silicon substrate; and then performing plasma assisted oxidation on said monocrystalline silicon substrate having the insulating layer and the patterned polycrystalline silicon-containing layer thereon, to thereby form recessed oxide isolation regions in the first predetermined regions of said monocrystalline silicon substrate, with minimal encroachment under the patterned polycrystalline silicon-containing layer and without oxidizing the polycrystalline silicon-containing layer on said monocrystalline silicon substrate during said plasma assisted oxidation step; and further patterning said polycrystalline silicon-containing layer to define second predetermined regions of said monocrystalline silicon substrate between said recessed oxide isolation regions and the polycrystalline silicon-containing layer.
Claim 23
Dependent Claim
150 words
A process for forming Maximum Areal Density Field Effect Transistor (MADFET) devices in a monocrystalline silicon substrate, comprising the steps of: forming an insulating layer on said monocrystalline silicon substrate; and then fabricating a patterned polycrystalline silicon-containing layer on said insulating layer, said patterned polycrystalline silicon-containing layer defining first predetermined regions of said monocrystalline silicon substrate; and then performing plasma assisted oxidation on said monocrystalline silicon substrate having the insulating layer and the patterned polycrystalline silicon-containing layer thereon, to thereby form recessed oxide isolation regions in the first predetermined regions of said monocrystalline silicon substrate, with minimal encroachment under the patterned polycrystalline silicon-containing layer and without oxidizing the polycrystalline silicon-containing layer on said monocrystalline silicon substrate during said plasma assisted oxidation step; and further patterning said polycrystalline silicon-containing layer to define second predetermined regions of said monocrystalline silicon substrate between said recessed oxide isolation regions and the polycrystalline silicon-containing layer.
Claim 24
Dependent Claim
36 words
The process of claim 20 further comprising the step of: forming source and drain regions in the second predetermined regions of the monocrystalline silicon substrate between the recessed oxide isolation regions and the polycrystalline silicon-containing layer.
Claim 25
Dependent Claim
12 words
The process of claim 20 wherein said insulating layer comprises silicon dioxide.
Claim 26
Dependent Claim
12 words
The process of claim 20 wherein said insulating layer is void free.
Claim 27
Dependent Claim
16 words
The process of claim 21 wherein said silicon dioxide layer is at least 7 nm thick.
Claim 28
Dependent Claim
25 words
The process of claim 20 wherein said polycrystalline silicon-containing layer is selected from the group consisting of undoped polycrystalline silicon, doped polycrystalline silicon and polycide.
Claim 29
Dependent Claim
20 words
The process of claim 20 wherein said plasma assisted oxidation is performed at temperatures between 300° C. and 700° C.
Claim 30
Dependent Claim
19 words
The process of claim 20 wherein said plasma assisted oxidation is performed at a temperature of about 500° C.
Claim 31
Dependent Claim
17 words
The process of claim 20 wherein said plasma assisted oxidation comprises radio frequency generated plasma assisted oxidation.
Claim 32
Dependent Claim
26 words
The process of claim 20 wherein said fabricating step is followed by the step of fabricating spacers on the sidewall of said patterned polycrystalline silicon-containing layer.
Claim 33
Dependent Claim
22 words
The process of claim 20 further comprising the step of forming source and drain contacts for said source and drain regions, respectively.
Claim 34
Dependent Claim
21 words
The process of claim 20 further comprising the step of forming a gate contact, electrically connected to said polycrystalline silicon-containing layer.
Claim 35
Dependent Claim
39 words
The process of claim 20 wherein said further patterning step comprises the steps of: forming a patterned second polycrystalline silicon-containing layer on said polycrystalline silicon-containing layer; and patterning said polycrystalline silicon-containing layer using said second patterned polycrystalline silicon-containing layer.
Claim 36
Dependent Claim
34 words
The process of claim 32 wherein said forming a patterned second polycrystalline silicon-containing layer step is followed by the step of forming a spacer on the sidewall of said patterned second polycrystalline silicon-containing layer.
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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) | 1994-08-12 | 1995-02-11 | 1995-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-12 | 1999-02-11 | 1999-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-12 | 2003-02-11 | 2003-08-13 | $7700.00 | Window Closed / Lapsed |