Advanced Tandem Gate Dielectrics for High-Temperature Electronics
Abstract
The objective of this project is to develop tandem gate dielectric stacks with an assembly of atomically thin Si3N4, HfxAl1-xOy, and SiO2 layers using in-situ atomic layer deposition (ALD), aiming to achieve low leakage current density, high bias stability, high breakdown field and superior reliability in wide bandgap transistors for high-temperature applications. Currently, the key limitation of wide bandgap CMOS transistors is the availability of high-quality gate dielectrics for high-temperature operation. Various gate dielectrics have been explored in the past; however, there is no single dielectric material that can satisfy all the requirements up to now, since each dielectric has its strengths and weaknesses. For example, SiO2 has a large band offset, but suffers from a low dielectric constant. HfO2 has a high dielectric constant, but low crystallization temperature, which causes a high leakage current at high temperature. Al2O3 has a high crystallization temperature, but a low dielectric constant. Si3N4 provides an excellent barrier for metal diffusion, but has a small conduction band offset. In this project, the PI proposes to explore a novel tandem dielectric structure, in which multiple types of dielectrics are assembled layer-by-layer using ALD deposition. This tandem dielectric will combine the strengths of the individual dielectrics and overcome their weaknesses. As compared to traditional dielectrics, the tandem dielectrics proposed here will have the advantages of low interface trap density, high bias stability, high thermal stability, and high breakdown field. In addition, these tandem dielectrics made by ALD will have excellent thickness control and conformal coverage on non-planar structures. The success of this project will provide a viable solution to dielectrics on wide bandgap materials for high-temperature electronics, which will have broad applications in the aerospace, automotive, and petrochemical industries.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 29, 2021
- Source ID
- HR00112010005
Entities
People
- Wenjuan Zhu
Organizations
- Defense Advanced Research Projects Agency
- University of Illinois system