Device having an anodic porous region surrounded by a trench having an electrical isolation barrier
An electrical device that includes: a metal barrier layer; an anodic porous oxide region on the metal barrier layer; a trench around the anodic porous oxide region reaching the metal barrier layer; a liner at least on a wall of the trench on a side of the anodic porous oxide region forming an electrical isolation barrier and having an opening onto the anodic porous oxide region; a hard mask arranged above the trenches and the liner having an opening onto the anodic porous oxide region. A corresponding manufacturing method is also disclosed.
1. An electrical device comprising:
a metal barrier layer;
an anodic porous oxide region on the metal barrier layer;
a trench around the anodic porous oxide region reaching the metal barrier layer;
a liner at least on a wall of the trench on a side of the anodic porous oxide region forming an electrical isolation barrier and having an opening onto the anodic porous oxide region; and
a hard mask arranged above the trenches and the liner having at least an opening onto the anodic porous oxide region.
2. The device of claim 1 , wherein the liner is arranged on both walls of the trench and on the bottom of the trench in a conformal manner.
3. The device of claim 1 , wherein a thickness of the hard mask is greater than half of a width of a void in the trench at least partially filled with the liner.
4. The device of claim 1 , wherein the liner is deposited so that a first remaining trench is arranged in the trench and:
the hard mask comprises an additional opening at a level of the first remaining trench, or
a thickness of the hard mask is chosen so that a second remaining trench is arranged in the first remaining trench.
5. The device of claim 1 , wherein a aspect ratio of the trench is below 2.
6. The device of claim 1 , wherein an edge of the opening of the hard mask is aligned with the wall of the trench on the side of the anodic porous oxide region or spaced by a given distance from the wall of the trench on the side of the anodic porous oxide region in a direction of a center of the anodic porous oxide region.
7. The device of claim 6 , wherein the given distance is greater than 500 nanometers.
8. The device of claim 1 , wherein a material of the liner is selected from silicon dioxide, silicon nitride, molybdenum, or tungsten.
9. The device of claim 1 , wherein the anodic porous oxide region comprises alumina.
10. The device of claim 1 , further comprising a capacitor including a first conductive layer, a first insulator layer covering the first conductive layer, and a second conductive layer covering the first insulator layer, the capacitor being inside pores of the anodic porous oxide region.
11. A method of manufacturing an electrical device comprising an anodic porous oxide region, the method comprising:
forming an anodizable metal layer on a metal barrier layer;
forming a trench in the anodizable metal layer around a portion of the anodizable metal layer which will include the anodic porous oxide region after anodizing, the trench reaching the metal barrier layer;
forming a liner at least on a wall of the trench on a side of a portion of the anodizable metal layer having an opening onto the anodic porous oxide region;
forming a hard mask above the trenches and the liner, having at least an opening onto the portion of the anodizable metal layer; and
anodizing the portion of the anodizable metal layer so as to obtain the anodic porous oxide region and form an electrical device that includes:
the metal barrier layer;
the anodic porous oxide region on the metal barrier layer;
the trench around the anodic porous oxide region and reaching the metal barrier laver;
the liner at least on the wall of the trench on a side of the anodic porous oxide region forming an electrical isolation barrier and having the opening onto the anodic porous oxide region; and
the hard mask arranged above the trenches and the liner having at least an opening onto the anodic porous oxide region.
12. The method of claim 11 , wherein forming the liner comprises depositing the liner on both walls of the trench and on a bottom of the trench in a conformal manner.
13. The method of claim 11 , wherein an edge of the opening of the hard mask is aligned with the wall of the trench on the side of the portion of the anodizable layer or spaced by a given distance (W2) from the wall of the trench on the side of the portion of the anodizable layer in the direction of a center of the portion.
14. The method of claim 11 , wherein forming the liner comprises depositing silicon dioxide or silicon nitride or molybdenum or tungsten.
15. The method of claim 11 , further comprising forming a capacitor including: forming a first conductive layer, forming a first insulator layer covering the first conductive layer, and forming a second conductive layer covering the first insulator layer, the capacitor being formed inside pores of the anodic porous oxide region.