(a) Transfer Characteristics of MZO HVTFTs. (b) Blocking capability and ON-performance of HVTFTs Schematic diagrams of a ring structure are shown.
Various materials have been tried for fabricating high voltage thin film transistors (HVTFTs), including amorphous-Si, poly-Si, and organic materials. However, these TFTs all have certain limitations, ranging from low blocking voltage, low ON-current, high cost, high process temperature, poor uniformity and stability, to complex fabrication process. These issues prevent the existing technologies being used as HVTFT on glass for solar inverters.
A research team led by Professor Yicheng Lu at Rutgers University has developed a novel Mg-doped zinc oxide (MZO)-based HVTFT on glass technology. MZO possesses a wide energy bandgap and a good thermal conductivity, which are critical for high voltage devices. In comparison with the pure zinc oxide TFT, MZO HVTFT shows better and uniform electrical performance and stability. The unique ring structure configuration of the MZO HVTFT on glass has superior electrical field distributions as compared to the conventional rectangular configuration, enabling mitigation of electrical field crowding and therefore leading to much enhanced blocking voltage capability. Further, the novel interface design and engineering prevent zinc diffusion from the channel to gate dielectric, therefore enhancing the electrical performance and increasing the blocking voltage.
Through these innovations, MZO HVTFT on glass provides a very high blocking voltage (>600 V) and a large ON/OFF current ratio (>109). The manufacturing process is fully compatible with the fabrication of conventional TFTs on glass.
Micro-Inverters in integrated photovoltaics system on glass (PV-SOG) for Building integrated photovoltaics (BIPV), self-powered smart glasses, high speed printers, digital radiology instruments.
- Low cost (materials, process), critically important for large-area electronics
- Novel device design and interface engineering lead to:
- High blocking voltage
- High stability
- High electrical performance and good uniformity
- High throughput for distributed micro-inverter tech
Intellectual Property & Development Status:
Patent pending. Available for licensing and/or research collaboration.
- MgZnO High Voltage Thin Film Transistors on Glass for Inverters in Building Integrated Photovoltaics. Hong WC, Ku CJ, Li R, Abbaslou S, Reyes P, Wang SY, Li GY, Lu M, Sheng K and Lu YC. (2016) Scientific Reports 6:34169.