Thyristor-based device with trench dielectric material
View Patent ↗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.
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.