Investigation of Scaling Limits for PECVD SiN and ALD HfO_2/Al_2O_3 Integrated MIM Capacitors

摘要

Scalability of MIM capacitors to higher capacitance densities is commonly limited by increasing leakage current and dielectric breakdown as the dielectric film is being made thinner. MIM Capacitors using PECVD SiN with up to 4 fF/μm~2 capacitance density and high-k ALD HfO_2/Al_2O_3 dielectrics with up 12 fF/μm~2 capacitance density have been developed and characterized for VLSI RF-CMOS and BiCMOS technologies with up to 5.5 V power supply voltage. Linearity, matching, and reliability were found to be generally degraded with increased capacitance density. Improved linearity could be achieved with dielectric film optimization and stacking of capacitors. TDDB lifetime of PECVD SiN MIM capacitors with 2.7 fF/μm~2 and of ALD high-k MIM capacitors with capacitance densities from 5 fF/μm~2 to 7.4 fF/μm~2 show suitability for applications up to 3.6 V using a conservative reliability model.