The Effect of the Dielectric Layer with Surface Plasma Treatment on Characteristics of Amorphous Silicon Antifuse

Abstract

With the advantages of lower capacitance, faster operation and smaller size, the amorphous silicon antifuse is very promising for high-speed and high-density FPGA. However, the leakage current of the conventional amorphous silicon antifuse in the off-state is high, which decreases its performance and reliability. Although the leakage current of the SiNX or SiOX antifuse is small, the proper thickness of the dielectric layer is not easily controlled by PECVD processes. In addition, the highly undesirable switch-off behavior is common to almost all metal-to-metal antifuse structures. Focusing on the study of amorphous silicon multilayer dielectric structures, a novel antifuse with the structure of Al/α-Si:H,N/α-Si:H/Al was proposed, which was manufactured by nitrogen plasma treatment for an α-Si:H film surface. Through surface plasma treatment, the hydrogen content of the dielectric layer is stable, the film surface is smoother, the leakage current is reduced, the switch-off behavior is eliminated, the programming voltage is more concentrated and the on-state resistance distribution is more compact. The results demonstrated that surface plasma treatment with proper time for the dielectric layer could significantly improve the performance and reliability of the Al/α-Si:H,N/α-Si:H/Al antifuse. Furthermore, the fabrication process of the α-Si:H,N/α-Si:H structure has excellent compatibility, controllability and simplicity.