A high-precision current measurement platform applied for statistical measurement of discharge current transient spectroscopy of traps in SiN dielectrics

This paper presents a current measurement platform to measure current across dielectrics with a high-precision of 10^-17 A from a large number of small capacitors at high speed. The developed platform consists of a common readout circuit part and a dielectric part formed on the circuit part by a simple process. A platform chip with 10 μm pitch 384^H × 360^V cells was fabricated using a 0.18 μm CMOS technology and silicon nitride (SiN) films were formed by plasma-enhanced CVD (PECVD) as a measurement target. The trap property of SiN films in metal–insulator–metal (MIM) capacitors was statistically measured by discharge current transient spectroscopy (DCTS) using the developed platform. The measured average energy levels of traps (E_c–E_t) were 0.21–0.25 eV, which is in good agreement with that of the discrete samples. The distributions of energy levels and densities of traps measured with different film thicknesses and areas are also presented and discussed.