SOI substrate fabrication
First Claim
1. A method for fabricating a silicon-on-insulator substrate, comprising:
- forming an etch-stop layer on a silicon device wafer;
forming a device layer on the etch-stop layer;
forming a dielectric layer on a silicon handle wafer;
making exposed surfaces of the dielectric layer and the device layer hydrophilic;
bonding the device layer and the dielectric layer at the exposed surfaces to each other at room temperature;
removing the silicon device wafer; and
removing the etch-stop layer wherein said removing steps are performed at room temperature.
1 Assignment
0 Petitions
Accused Products
Abstract
A back-etch silicon-on-insulator SOI process that has a silicon handle wafer with an oxide layer bonded at room temperature to a silicon device wafer with an etch stop and silicon device layer. The surfaces that are bonded at room temperature are first conditioned to be hydrophilic. After bonding, the edges of the layers are sealed. The silicon device wafer, the etch-stop layer and the device layer are boron doped. Most of the silicon device wafer is ground away. Then, the remaining portion of the silicon device wafer and the etch stop layer are chemically etched away, thereby leaving a uniform layer of silicon device layer on the oxide layer of the silicon handle wafer. Because the bonding, grinding and selective etching are performed at room temperature, inter-diffusion of the boron between the various layers is prevented and thus permits the selective etching process to result in a nearly perfect silicon device layer in terms of an even-surfaced, defect-free and thin layer on the buried oxide layer of silicon handle wafer. The resulting SOI wafer is then annealed at a high temperature, prior to device processing.
-
Citations
19 Claims
-
1. A method for fabricating a silicon-on-insulator substrate, comprising:
-
forming an etch-stop layer on a silicon device wafer; forming a device layer on the etch-stop layer; forming a dielectric layer on a silicon handle wafer; making exposed surfaces of the dielectric layer and the device layer hydrophilic; bonding the device layer and the dielectric layer at the exposed surfaces to each other at room temperature; removing the silicon device wafer; and removing the etch-stop layer wherein said removing steps are performed at room temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A method for fabricating a silicon-on-insulator substrate, comprising:
-
oxidizing a surface of a silicon handle wafer, resulting in an oxidized surface on the silicon handle wafer; epitaxially depositing a highly boron doped (p++) single crystal layer as an etch-stop layer on a surface of a silicon device wafer; epitaxially depositing lightly boron doped (p-) silicon layer as a device layer on the etch-stop layer; conditioning a first surface of the silicon device layer and the oxidized surface of the silicon handle wafer to be hydrophilic; bonding, at room temperature, the first surface of the silicon device layer and the oxidized surface of the silicon handle wafer to each other, resulting in bonded surfaces; sealing the bonded surfaces at a bond perimeter with a sealant; removing a significant portion of the silicon device wafer by grinding; etching away the remaining portion of the silicon device wafer; etching away the etch-stop layer, to expose a second surface of the silicon device layer wherein said removing and etching steps are performed at room temperature; and annealing the bonding of the first surface of the silicon device layer and the oxidized surface of the silicon handle wafer. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
-
Specification