Abstract A fabrication method for forming SOI structures where perfect material is grown epitaxially on a substrate and then, through a series of selective etches and oxidations, an insulating layer is formed below the epitaxial silicon. In the method, low temperature epitaxial techniques are employed to grow a layered structure including a first layer p++ silicon on a substrate wafer, a layer of intrinsic silicon is then formed on the first p++ silicon layer, and a second layer of p++ silicon is formed on the intrinsic silicon layer, and a finally a layer of p-silicon is fabricated on top of the second p++ silicon layer. Grooves are formed through the p-layer, the second p++ silicon layer, the intrinsic silicon layer, and stopped in the first p++ silicon layer. An etch is then employed to remove the intrinsic layer long enough for the p++ silicon layer to be totally undercut, leaving an air gap between the two p++ silicon layers. An oxidation step is then performed to form a bottom insulator consisting of the oxidized first p++ silicon layer and on an upper insulator consisting of the oxidized second p++ silicon layer.
A method for fabricating a silicon-on-insulator structure comprising the steps of: Step 1: forming a first layer of p++ silicon on a silicon substrate; Step 2: forming a layer of intrinsic silicon on said first layer of p++ silicon; Step 3: forming a second layer of p++ silicon on said layer of intrinsic silicon; Step 4: forming a layer of p- silicon on said second layer of p++ silicon; Step 5: forming at least one groove through said layer of p- silicon, said second layer of p++ silicon, said intrinsic layer and into said first layer of p++ silicon; Step 6: filling said at least one groove with suitable material; Step 7: and removing said layer of intrinsic silicon to provide an air gap space wherein said layer of p- silicon and said second layer of p++ silicon are supported above said air gap by said at least one filled groove extending into said first layer of p++ silicon below said air gap space.
Claim 2
Independent Claim
164 words
A method for fabricating a silicon-on-insulator structure comprising the steps of: Step 1: forming a first layer of p++ silicon on a silicon substrate; Step 2: forming a layer of intrinsic silicon on said first layer of p++ silicon; Step 3: forming a second layer of p++ silicon on said layer of intrinsic silicon; Step 4: forming a layer of p- silicon on said second layer of p++ silicon; Step 5: forming at least one groove through said layer of p- silicon, said second layer of p++ silicon, said intrinsic layer and into said first layer of p++ silicon; Step 6: filling said at least one groove with suitable material; Step 7: and removing said layer of intrinsic silicon to provide an air gap space wherein said layer of p- silicon and said second layer of p++ silicon are supported above said air gap by said at least one filled groove extending into said first layer of p++ silicon below said air gap space.
Claim 3
Dependent Claim
34 words
A method according to claim 1 further including the step of Step 8: oxidizing said first and second p++ layers to form insulating layers of silicon dioxide above and below said air gap space.
Claim 4
Dependent Claim
36 words
A method according to claim 1 further including the step of Step 8: wet etching said first and second p++ layers and oxidizing to form layers of silicon dioxide above and below said air gap space.
Claim 5
Dependent Claim
19 words
A method according to claim 1 wherein said material filling said at least one groove is electrically insulating material.
Claim 6
Dependent Claim
18 words
A method according to claim 1 wherein said material filling said at least one groove is silicon dioxide.
Claim 7
Dependent Claim
17 words
A method according to claim 1 wherein said material filling said at least one groove is BPSG.
Claim 8
Dependent Claim
18 words
A method according to claim 1 wherein said material filling said at least one groove is electrically conducting.
Claim 9
Dependent Claim
17 words
A method according to claim 1 wherein said material filling said at least one groove is polysilicon.