Ultra high density capacity comprising pillar-shaped capacitors formed on both sides of a substrate
The present invention describes an ultra High-Density Capacitor design, integrated in a semiconductor substrate, preferably a Si substrate, by using both wafer sides. The capacitors are pillar-shaped and comprise electrodes ( 930,950 ) separated by a dielectric layer ( 940 ). Via connections ( 920 ) are provided in trenches that go through the whole thickness of the wafer.
1. Semiconductor device with an ultra high density capacitor, comprising a silicon substrate, more than one pillar like structure on the front side and back side of the silicon substrate, at least one trench extending through the substrate, a capacitor top electrode contact, and a capacitor bottom electrode contact, wherein the pillar structures comprise, seen from core to shaft, an inner conductive material, a dielectric material and an outer conductive material, wherein the trench comprises, seen from center to wall thereof, the inner conductive material, the dielectric material and the outer conductive material,
wherein the inner conductive material is poly silicon and the outer conductive material is doped silicon, and
wherein the top electrode contact is connected to the inner conductive material and the bottom electrode contact is connected to the outer conductive material.
2. Semiconductor device according to claim 1 , wherein the width of the trench is from 0.5 to 2.0 times the shortest distance between the doped silicon of two adjacent pillars.
3. Semiconductor device according to claim 1 , wherein the at least one trench is designed in a such way that the total open area of the at least one trench is bigger than the capacitor area.
4. A device selected from the group consisting of a MEMS device, a microbattery, integrated capacitors, and a Si-integrated component, the device comprising a semiconductor device according to claim 1 .
5. A mobile application comprising a device according to claim 4 and/or a semiconductor device according to claim 1 .
6. Method of manufacturing a semiconductor device according to claim 1 , comprising:
providing a silicon substrate,
forming at least one trench and pillar holes on one side of the silicon substrate,
forming at least one trench and pillar holes on an other side of the silicon substrate, whereby trenches go through the silicon substrate,
doping an outer surface of the silicon substrate, to create a first electrode, which is referred to as a bottom electrode, which reference is both applicable for a front and a back side of silicon substrate, and simultaneously create a front side and back side connection as a via,
forming a layer of dielectric material on both sides of the silicon substrate, and thus also into the via, and the pillar holes,
forming a poly silicon layer on both sides of the silicon substrate, to create a second electrode and simultaneously create a front side and back side connection in the via,
etching a first side of the silicon substrate, in order to pattern a top electrode,
etching a second side of the silicon substrate, in order to pattern a top electrode on the second side of the wafer, and
forming contacts to the electrodes.