A Novel Scalable Series MIM Capacitor Model for MMIC Applications

With the development of the wireless communication and integrated circuits, Integrated passive devices (IPDs) have gained more and more application in radio frequency (RF) integrated circuit and monolithic microwave integrated circuits (MMICs). Among IPDs, MIM capacitor is a key passive component, widely used in DC-bias circuit, decoupling, etc. Therefore, the accuracy and practicability of the capacitance model is one of the key factors for the success of circuits design.However, since the MIM capacitor has many parasitic effects at high frequencies, it no longer exhibits pure capacitor characteristics anymore, thus, in high frequency circuit design, a simplified equivalent circuit model that can accurately characterizes the components is essential for the successful design of the circuit.As SiC-based GaN devices exhibit the advantages of high temperature and high power in millimeter wave applications, more and more integrated circuit use SiC-based GaN devices and components. With regards to this we produced a series of MIM capacitors of different sizes with air-bridges have been fabricated on 4H–SiC substrate. Also, we proposed a novel of simple broadband, based on the physical parameter equivalent circuit model of MIM capacitor structure.Based on the traditional equivalent circuit model, we introduce the corresponding components that characterize the skin effect and loss of the metal. The lumped element model is a simplified physical based model with broadband and high precision, and parameter extraction is given. To verify the accuracy and versatility of the model, we compared the measured and model simulated results of a series of MIM capacitors of different sizes. The results show that the model can accurately fit the S-parameters between measured and simulated in operating frequency range. In addition, the model shows good scalability as well.