Millimetre wave integrated circuits with thin film transistors

A fabrication method for a MMIC with a thin film transistor of a planar semiconductor channel layer, a thin film capacitor and a thin film resistor where post fabrication substrate grinding and etching is not needed comprises:

• selecting a dielectric substrate;
• depositing a first dielectric layer having a first dielectric layer thickness;
• etching selectively portions of said first dielectric layer to form a first metal gate head portion cavity and a first capacitor electrode cavity;
• depositing a first metal layer having a first metal layer thickness substantially greater than said first dielectric layer thickness;
• performing a first chemical and mechanical polishing to create a first metal gate head portion and a first capacitor electrode, said first metal gate head portion and said first capacitor electrode are embedded in said first dielectric layer;
• depositing a second dielectric layer with a second dielectric layer thickness;
• etching selectively a portion of said second dielectric layer to form a first metal gate stem portion cavity;
• depositing a second metal layer having a second metal layer thickness substantially greater than said second dielectric layer thickness;
• performing a second chemical and mechanical polishing to create a first metal gate stem portion, said first metal gate stem portion is embedded in said second dielectric layer and is in direct electric contact with said first metal gate head portion;
• depositing a third dielectric layer having a third dielectric layer thickness;
• depositing and patterning a first thin film resistor layer having a first thin film resistor layer thickness;
• depositing and patterning a first semiconductor channel layer having a first semiconductor channel layer thickness;
• depositing and patterning a drain ledge layer and a source ledge layer having a ledge layer thickness and a ledge layer gap;
• depositing and patterning a drain, a source and a second capacitor electrode, said second capacitor electrode overlaps at least a portion of said first capacitor electrode;
• depositing and patterning a first resistor contact and a second resistor contact;
• depositing a fourth dielectric layer for protection and passivation of said thin film transistor;
• depositing a resistor dielectric layer for protection and passivation of said thin film resistor;
• and
• depositing a back metal layer on a back side of said dielectric substrate to complete the fabrication processes of a MMIC.