Frequency Modulated Charge Pumping with Extremely High Gate Leakage
Jason T. Ryan, Jibin Zou, Jason P. Campbell, Richard Southwick, Kin P. Cheung, Anthony Oates, Rue Huang
Charge pumping (CP) has proven itself as one of the most utilitarian methods to quantify defects in metal-oxide-semiconductor devices. In the presence of low to moderate gate leakage, CP quantification is most often implemented via a series of measurements at multiple frequencies. However, this approach is ill-equipped to handle excessive leakage currents common in advanced technologies. In this work, we transform multi-frequency CP from a quasi-DC measurement into a true AC measurement. This AC detection scheme, called frequency-modulated charge pumping, is far better equipped to deal with high levels of leakage currents and thereby extends the usefulness of CP to current and future device technologies where excessive leakage is the norm. Additionally, we show that multi-frequency CP has a long overlooked error that becomes significant in high leakage situations. We discuss the origins of this error in detail and outline mitigation methodologies. Finally, we explore timing and voltage limitations of waveform generators and how these experimental boundary conditions impact both frequency-dependent as well as frequency-modulated CP.