Next generation power electronic systems for military aircraft will require capacitors with reliable performance at temperatures from -55 up to 300 degrees C and beyond for filters, power converters and other control circuitry. Thin film integrated passive devices with lower dissipation and electrical leakage will also be needed, especially at high frequencies. Thin films have inherently high breakdown strengths, and high quality thin film dielectrics of barium strontium titanate (BST) have been shown to have superior charge storage density. Further, modification of BST of certain B-site dopants results in lower dissipation and reduced eletrical degradation at elevated temperature. A deposition technology to produce high quality films which is compatible with integrated technologies will be required for these devices. Metalorganic chemical vapor deposition (MOCVD) offers a unique combination of composition control, scalability, and the ability to produce extremely dense, low defect films. In Phase I, an MOCVD process to deposit B-site modified BST will be developed and the films will be characterized for capacitance, leakage, and loss at temperatures up to 300 degrees C. In Phase II, the process will be optimized based on electrical properties and long term reliability will be assessed at elevated temperature and electric field.
Benefits: Military applications for the high temperature capacitors proposed herein include the More Electric Plane, multi-chip modules, and a variety of high powered circuitry in radars, weapon systems, etc. Civilian needs include commercial aircraft, geophysical exploration, and harsh environments such as nuclear power stations and satellites.
