IMPACT OF STATE-OF-THE-ART Cz SUBSTRATES ON THE CURRENT-VOLTAGE CHARACTERISTICS OF SHALLOW p-n JUNCTIONS

摘要

This paper studies the impact of state-of-the-art Czochralski (Cz) substrates on the current-voltage (I-V) characteristics of shallow n~+-p-well junctions surrounded by polysilicon encapsulated local oxidation of silicon (PELOX). The Cz substrates contain different densities of Crystal Originated Particles (COP) and interstitial oxygen (O_i). The overall yield is excellent. The yield can be improved when the leakage current (I_R) is dominated by the peripheral (I_P), corner (I_C) or area (I_A) component, in descending order by reducing the COP density. Reducing the O_i density improves the yield when I_R is dominated by I_A and I_P but reduces it when I_K is dominated by I_C. The I-V characteristic of the good low-leakage diodes is not much different for different wafers. This allows to conclude that the processing-induced defect density in a 0.18 μm CMOS technology is higher than the defect density in the starting material.