Methods for forming shielded gate field effect transistors
First Claim
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1. A method for forming a field effect transistor comprising:
- forming a trench in a semiconductor region;
forming a dielectric layer lining the trench sidewalls and bottom;
filling the trench with a conductive material;
recessing the conductive material into the trench to thereby form a shield electrode in a bottom portion of the trench;
after the recessing step, removing exposed portions of the dielectric layer whereby the dielectric layer is recessed in the trench to below a top surface of the shield electrode;
recessing the shield electrode so that a top surface of the recessed shield electrode is substantially coplanar with a top surface of the recessed dielectric layer; and
forming an inter-electrode dielectric (IED) over the recessed shield electrode.
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Abstract
A field effect transistor is formed as follows. A trench is formed in a semiconductor region. A dielectric layer lining the trench sidewalls and bottom is formed. The trench is filled with a conductive material. The conductive material is recessed into the trench to thereby form a shield electrode in a bottom portion of the trench. The recessing of the conductive material includes isotropic etching of the conductive material. An inter-electrode dielectric (IED) is formed over the recessed shield electrode.
77 Citations
18 Claims
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1. A method for forming a field effect transistor comprising:
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forming a trench in a semiconductor region; forming a dielectric layer lining the trench sidewalls and bottom; filling the trench with a conductive material; recessing the conductive material into the trench to thereby form a shield electrode in a bottom portion of the trench; after the recessing step, removing exposed portions of the dielectric layer whereby the dielectric layer is recessed in the trench to below a top surface of the shield electrode; recessing the shield electrode so that a top surface of the recessed shield electrode is substantially coplanar with a top surface of the recessed dielectric layer; and forming an inter-electrode dielectric (IED) over the recessed shield electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for forming a field effect transistor comprising:
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forming a trench in a semiconductor region; forming a dielectric layer lining the trench sidewalls and bottom; filling the trench with a conductive material; recessing the conductive material into the trench to thereby form a shield electrode in a bottom portion of the trench; after the recessing step, removing exposed portions of the dielectric layer whereby the dielectric layer is recessed in the trench to below a top surface of the shield electrode; recessing the shield electrode to below a top surface of the recessed dielectric layer; and forming an inter-electrode dielectric (IED) over the recessed shield electrode. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification