Aluminum nitride deposition using an AlN/Al sputter cycle technique

Claim 1

A method of fabricating a thin film resonator comprising at least one dielectric thin film layer sandwiched between two conductive thin film electrode layers, the method comprising the steps of: (a) depositing a smooth, uniform metal layer on a substrate to serve as a first electrode; (b) placing the substrate with deposited first electrode in a DC magnetron reactive sputtering system for an extended deposition cycle to product the dielectric thin film, the reactive sputtering system including a chamber having interior and exterior surfaces; (c) initiating a sputtering cycle with a pure aluminum target and a nitrogen reactive gas to form the dielectric thin film comprising a thin uniform highly-oriented aluminum nitride film on the first electrode; (d) interrupting the sputtering cycle while the dielectric aluminum nitride film is being formed but before a highly insulating film of aluminum nitride is grown on the chamber interior and, during said interruption: (i) shielding the substrate with deposited first electrode and partially formed dielectric aluminum nitride film; and (ii) temporarily introducing an inert gas in place of the reactive gas to deposit a thin conductive film over the highly insulating aluminum nitride film grown on the chamber interior to prevent contamination of the dielectric aluminum nitride film; (e) repeating steps (c) and (d) until the dielectric aluminum nitride film deposited on the first electrode is o the desired thickness; and (f) depositing a second metal electrode over the dielectric thin film, thereby to produce a resonator with smooth electrodes encompassing a thin, highly-oriented piezoelectric film substantially free of contaminants dislodged from the reactive sputtering system.

Claim 2

A method of fabricating a thin film resonator comprising at least one dielectric thin film layer sandwiched between two conductive thin film electrode layers, the method comprising the steps of: (a) depositing a smooth, uniform metal layer on a substrate to serve as a first electrode; (b) placing the substrate with deposited first electrode in a DC magnetron reactive sputtering system for an extended deposition cycle to product the dielectric thin film, the reactive sputtering system including a chamber having interior and exterior surfaces; (c) initiating a sputtering cycle with a pure aluminum target and a nitrogen reactive gas to form the dielectric thin film comprising a thin uniform highly-oriented aluminum nitride film on the first electrode; (d) interrupting the sputtering cycle while the dielectric aluminum nitride film is being formed but before a highly insulating film of aluminum nitride is grown on the chamber interior and, during said interruption: (i) shielding the substrate with deposited first electrode and partially formed dielectric aluminum nitride film; and (ii) temporarily introducing an inert gas in place of the reactive gas to deposit a thin conductive film over the highly insulating aluminum nitride film grown on the chamber interior to prevent contamination of the dielectric aluminum nitride film; (e) repeating steps (c) and (d) until the dielectric aluminum nitride film deposited on the first electrode is o the desired thickness; and (f) depositing a second metal electrode over the dielectric thin film, thereby to produce a resonator with smooth electrodes encompassing a thin, highly-oriented piezoelectric film substantially free of contaminants dislodged from the reactive sputtering system.

Claim 5

A method for forming thin films of a dielectric material which exhibit improved quality and piezoelectric response, the dielectric thin films being formed in a DC magnetron reactive sputtering system in the presence of a reactive gas and deposited on a substrate located within a chambers of the sputtering system with the chamber having interior and exterior surfaces, the method comprising the steps of: depositing the dielectric material on the substrate; interrupting the step of depositing dielectric material while the dielectric thin film is being formed but before a highly insulating film is grown on the chamber interior; replacing the reactive gas with an inert gas during the step of interrupting and depositing a layer of conductive metal on the chamber interior in order to conceal the highly insulating film thereby reducing contamination and improving the quality and piezoelectric response of the dielectric thin films; shielding the substrate with partially deposited dielectric material during the step of depositing the conductive metal layer in order to prevent metal from being deposited on the substrate with partially deposited dielectric material; and repeatedly alternating the deposition of the dielectric material on the substrate and the metal layer on the chamber interior until a desired thickness of the dielectric thin film has been reached.

Claim 6

A method for forming thin films of a dielectric material which exhibit improved quality and piezoelectric response, the dielectric thin films being formed in a DC magnetron reactive sputtering system in the presence of a reactive gas and deposited on a substrate located within a chambers of the sputtering system with the chamber having interior and exterior surfaces, the method comprising the steps of: depositing the dielectric material on the substrate; interrupting the step of depositing dielectric material while the dielectric thin film is being formed but before a highly insulating film is grown on the chamber interior; replacing the reactive gas with an inert gas during the step of interrupting and depositing a layer of conductive metal on the chamber interior in order to conceal the highly insulating film thereby reducing contamination and improving the quality and piezoelectric response of the dielectric thin films; shielding the substrate with partially deposited dielectric material during the step of depositing the conductive metal layer in order to prevent metal from being deposited on the substrate with partially deposited dielectric material; and repeatedly alternating the deposition of the dielectric material on the substrate and the metal layer on the chamber interior until a desired thickness of the dielectric thin film has been reached.

Claim 11

A method for preventing contamination of thin films of a dielectric material formed in a DC magnetron reactive sputtering system, the dielectric thin films being deposited on a substrate located in a chamber of the sputtering system in the presence of a reactive gas with the chamber having interior and exterior surfaces, the method comprising the steps of: (a) depositing the dielectric material onto the substrate; (b) interrupting the step of depositing dielectric material while the dielectric thin film is being formed but before a highly insulating film is grown on the chamber interior; (c) removing the reactive gas from the chamber; (d) shielding the substrate with partially deposited dielectric material in order to temporarily prevent deposition from occurring thereon; (e) introducing an inert gas into the chamber; (f) depositing a layer of conductive metal on the chamber interior in order to conceal the highly insulating film on the chamber interior thereby reducing contamination and improving he quality and piezoelectric response of the dielectric thin films; (g) removing the inert gas and reintroducing the reactive gas into the chamber; (h) uncovering the substrate with partially deposited dielectric material; and (i) repeatedly performing steps (a) through (h) until a desired amount of dielectric material is deposited on the substrate.

Claim 12

A method for preventing contamination of thin films of a dielectric material formed in a DC magnetron reactive sputtering system, the dielectric thin films being deposited on a substrate located in a chamber of the sputtering system in the presence of a reactive gas with the chamber having interior and exterior surfaces, the method comprising the steps of: (a) depositing the dielectric material onto the substrate; (b) interrupting the step of depositing dielectric material while the dielectric thin film is being formed but before a highly insulating film is grown on the chamber interior; (c) removing the reactive gas from the chamber; (d) shielding the substrate with partially deposited dielectric material in order to temporarily prevent deposition from occurring thereon; (e) introducing an inert gas into the chamber; (f) depositing a layer of conductive metal on the chamber interior in order to conceal the highly insulating film on the chamber interior thereby reducing contamination and improving he quality and piezoelectric response of the dielectric thin films; (g) removing the inert gas and reintroducing the reactive gas into the chamber; (h) uncovering the substrate with partially deposited dielectric material; and (i) repeatedly performing steps (a) through (h) until a desired amount of dielectric material is deposited on the substrate.