To overcome the physical limit in the device scaling, the monolithic 3D-IC technology with back-end-of-line process compability (<400 ˚C ) has received a lot of attention and been studied to replace typical 2D-IC circuit layouts. It can effectively increase circuit integration density in a single wafer and further reduce power consumption. 
In this project, we have successfully developed the HC-TFTs with N-type InWO (a-IWO) TFT and P-type polycrystaline Si (poly-Si) TFT, where a-IWO was designed with a junctiomless device configuration. The a-IWO TFT exhibited low operating voltage, low leakage currents and the absence of short channel effect due to the nano-sheet channel structure. The P-type poly-Si TFT, fabricated by LC-NILC technology can effectively reduce the content of nickel contaminants, and improve the electrical characteristics and reliability of the TFT device. A complete TCAD device model for the HC-TFT also was established for the CMOS inverter applications.

Through silicon via (TSV) technology has been adopted to achieve multi-chip modules with different IC functions for applications in the 3D-IC package architecture. However, the TSV technology suffers many challenges due to the limit in circuit layout and causing the decreased yield. Monolithic 3D-IC technology is expected to replace the TSV due to its ease of manufacture, short interconnections, lower power consumption, and lower cost. In this research, we have successfully developed the high-performance HC-TFTs comprised of N-channel a-IWO nano-sheet TFT and P-channel poly-Si TFT for monolithic 3D CMOS-based inverter applications. The technological breakthroughs are not only applied to 3D-IC, but can also be extended to ultra-high resolution flat-panel display backplane technology.

This project has successfully developed a 3D-IC-based CMOS inverter circuit with high performance and low power consumption, which can be implemented in advanced electronic products. Also, the novel HC-TFT CMOS technology can be applied to flat-panel displays to construct the complete driving circuits and make the design of display circuits flexible, enhancing the diversity and added values.