Thyristor-based device with trench dielectric material

• US 7,374,974 B1
• Filed: 03/05/2004
• Issued: 05/20/2008
• Est. Priority Date: 03/22/2001
• Status: Expired due to Fees

• Current Assignee: T-Ram, LLC
• Original Assignee: T-RAM Semiconductor, Inc.
• Inventors: Horch, Andrew, Robins, Scott
• Primary Examiner(s): Coleman, W. David
• Assistant Examiner(s): Kim, Su C.
• Application Number:
  US10/794,843
• Time in Patent Office: 1,537 Days
• Field of Search: 438/133, 438/292, 438/295, 438/134, 438/135, 438/296, 438/137, 438/115, 257/E21.39, 257/E21.392, 257/E21.614, 257/E21.677, 257/E21.388, 257/E21.389
• US Class Current: 438/133
• CPC Class Codes: H01L 29/66378 the other device being a controlling field-effect device
• CPC Class Codes: H01L 29/742 the device being a field effect transistor for turn-on or turn-off by field effect H01L29/745, H01L29/749
• CPC Class Codes: H01L 29/749 with turn-on by field effect

Abstract

A thyristor-based semiconductor device includes a thyristor body that has at least one region in the substrate and a thyristor control port in a trenched region of the device substrate. According to an example embodiment of the present invention, the trench is at least partially filled with a dielectric material and a control port adapted to capacitively couple to the at least one thyristor body region in the substrate. In a more specific implementation, the dielectric material includes deposited dielectric material that is adapted to exhibit resistance to voltage-induced stress that thermally-grown dielectric materials generally exhibit. In another implementation, the dielectric material includes thermally-grown dielectric material, and when used in connection with highly-doped material in the trench, grows faster on the highly-doped material than on a sidewall of the trench that faces the at least on thyristor body region in the substrate. In still another implementation, the dielectric material includes both a thermally-grown dielectric material and a deposited dielectric material. These approaches are particularly useful, for example, in high-density and other applications where thermally-stable dielectric materials are desirable and/or where dielectric material growth at different rates is desirable.

Claims

1. A method of manufacturing a semiconductor device having a substrate, the method comprising:

forming a thyristor having at least a portion of the thyristor'"'"'s body region in and formed from the substrate;

forming a trench in the substrate adjacent to the at least one portion of the thyristor'"'"'s body region;

forming conductive filler material in the trench;

forming a control port in the trench, the control port being configured and arranged to capacitively couple to the thyristor body region for controlling current flow therein; and

forming a dielectric material in the trench to at least partially fill the trench and electrically insulates the conductive filler material from the control port;

wherein forming the dielectric material in the trench includes thermally growing the dielectric material in the trench; and

wherein thermally growing the dielectric material in the trench includes thermally growing the dielectric material on the conductive filler material at a first growth rate and thermally growing the dielectric material on a sidewall of the trench at a second growth rate, the first growth rate being higher than the second growth rate.

2. The method of claim 1 wherein forming the control port in the trench includes forming the control port on the dielectric material thermally grown on the conductive filler material.

3. The method of claim 1, wherein the thyristor is a capacitively-coupled thyristor.

4. The method of claim 1, further comprising forming a memory cell, by forming the transistor electrically coupled in series with the thyristor body'"'"'s region.

5. The method of claim 1, wherein forming the trench in the substrate includes forming the trench having an aspect ratio of a height to width greater than 2:

1.