Adhering layers to metals with dielectric adhesive layers
View Patent ↗The present invention provides a method for adhering dielectric layers to metals, in particular inert metals, using an adhesive layer comprising silicon-rich silicon nitride. Good adhesion is achieved at temperatures of less than 300° C., thereby facilitating the fabrication of semiconductor structures containing II–VI and III–V semiconductors.
1. A semiconductor structure comprising:
a substrate;
a metal layer over said substrate;
an adhesive layer of silicon-rich silicon nitride on said metal layer;
a dielectric layer on said adhesive layer, said dielectric layer having a lower stoichiometric silicon content than said adhesive layer; and
a second metal on said dielectric layer,
wherein said metal and said second metal form plates of a capacitor.
2. A semiconductor structure comprising:
a substrate:
a metal layer over said substrate;
an adhesive layer of silicon-rich silicon nitride on said metal layer;
a dielectric layer on said adhesive layer, said dielectric layer having a lower stoichiometric silicon content than said adhesive layer; and
a second adhesive layer between said substrate and said metal layer.
3. The structure as recited in claim 1 , wherein said adhesion layer comprises a dielectric compound having a stoichiometric ratio of silicon to nitrogen of greater than about 1.
4. The structure as recited in claim 1 , wherein said adhesion layer comprises a dielectric compound having a stoichiometric ratio of silicon to nitrogen of between about 1.2 and about 1.5.
5. A semiconductor structure comprising:
a substrate;
a metal layer over said substrate;
an adhesive layer of silicon-rich silicon nitride on said metal layer; and
a dielectric layer on said adhesive layer said dielectric layer having a lower stoichiometric silicon content than said adhesive layer,
wherein said adhesive layer has a refractive index between about 2.3 and about 2.7 at a wavelength of about 632 nm.
6. An integrated circuit, comprising:
bipolar transistor, including a collector, a base, and emitter on a semiconductor substrate; and
a capacitor over said semiconductor substrate, including:
a metal layer over said semiconductor substrate;
an adhesive layer of silicon-rich silicon nitride on said metal layer;
a dielectric layer, having a lower silicon content than said adhesive layer, on said adhesive layer; and
a second metal layer over said dielectric layer.
7. The integrated circuit as recited in claim 6 , wherein said adhesive layer comprises a dielectric material having a stoichiometric ratio of silicon to nitrogen of greater than about 1.
8. The integrated circuit as recited in claim 6 , wherein said adhesion layer comprises a dielectric material having a stoichiometric ratio of silicon to nitrogen of between about 1.2 and about 1.5.