Charge pumping and DCIV currents in SOI FinFETs

Abstract

Charge pumping (ACIV) and direct current–voltage (DCIV) measurements were performed on standard floating-body n-channel FinFETs. The resulting recombination currents are monitored directly at the drain and source contacts, and are found to depend strongly on frequency, gate voltage, and FinFET geometry. The DCIV current reaches a maximum when the body potential transitions from accumulation to inversion in response to the applied gate bias and the body-to-source and body-to-drain diodes become forward biased. The ACIV current is dominated by contributions from interface traps when the surface potential is swept from accumulation to inversion during the gate pulse. It is sensitive to recombination currents at the body-to-source and body-to-drain diodes at intermediate voltage levels. At the highest applied gate voltages, band-to-band tunneling is also observed. We demonstrate that the change in ACIV current with frequency before and after electrical stress allows charge-pumping estimates of stress-induced interface trap densities in standard SOI FinFETs without body contacts.