Passivation and alignment of piezoelectronic transistor piezoresistor
A method of forming a piezoelectronic transistor (PET) device, the PET device, and a semiconductor including the PET device are described. The method includes forming a first metal layer, forming a layer of a piezoelectric (PE) element on the first metal layer, and forming a second metal layer on the PE element. The method also includes forming a well above the second metal layer, forming a piezoresistive (PR) material in the well and above the well, and forming a passivation layer and a top metal layer above the PR material at the diameter of the PR material above the well, wherein a cross sectional shape of the well, the PR material above the well, the passivation layer, and the top metal layer is a T-shaped structure. The method further includes forming a metal clamp layer as a top layer of the PET device.
1. A method of forming a piezoelectronic transistor (PET) device, the method comprising:
forming a first metal layer;
forming a layer of a piezoelectric (PE) element on the first metal layer;
forming a second metal layer on the PE element;
forming a well above the second metal layer, sides of the well being lined with a passivation film;
forming a piezoresistive (PR) material in the well and above the well, a diameter of the PR material above the well being greater than a diameter of the well;
forming a passivation layer and a top metal layer above the PR material at the diameter of the PR material above the well, wherein a cross sectional shape of the well, the PR material above the well, the passivation layer, and the top metal layer is a T-shaped structure; and
forming a metal clamp layer as a top layer of the PET device.
2. The method according to claim 1 , further comprising forming a spring on the second metal layer adjacent to the T-shaped structure.
3. The method according to claim 2 , further comprising forming vias above the top metal layer, wherein the forming the metal clamp layer includes connecting the metal clamp layer with the spring and the T-shaped structure through the vias.
4. The method according to claim 2 , wherein the forming the spring includes forming a silicon layer on the second metal layer, depositing a spring metal such that a portion of the spring metal is on the silicon layer and a portion of the spring metal is on the second metal layer, and etching the silicon layer such that the portion of the spring metal on the silicon layer is cantilevered above the second metal layer.
5. The method according to claim 4 , wherein the depositing the spring metal includes depositing ruthenium (Ru) and titanium nitride (TiN).
6. The method according to claim 1 , further comprising aligning the metal clamp layer based on the diameter of the PR material above the well to ensure a close contact between the PR material in the well and the second metal layer above the PE element.
7. The method according to claim 1 , wherein the forming the well is based on electron beam lithography.
8. The method according to claim 1 , further comprising lining an edge of the T-shaped structure above the well with the passivation film.