Yu-Hsing Cheng, Staff Engineer, Corporate Research and Development, ON Semiconductor
Yu-Hsing Cheng joined ON Semiconductor in 2000 after receiving the M.S. in electrical engineering from Brown University. He has been a member in the technology development team of ON Semiconductor in East Greenwich, RI since 2000 with a focus on device characterization in BCD processes. He has developed the architecture of parametric testing without any software packages and designed the methodology for efficient and flexible test development with extensive data collection for device evaluation. Currently he is a Staff Engineer in Corporate Research and Development group and is working on device development, characterization, and data analysis of smart power technologies.
Comparative Analysis of Practical Threshold Voltage Extraction Techniques for CMOS and LDMOS Devices in 180 nm Technology
Threshold voltage VT is a fundamental parameter in MOSFET device characterization and modeling. Yet there is no single and clear definition for threshold voltage VT, as the transition from weak inversion to moderate and strong inversion is very gradual. The classical definition of energy band bending for VT, while conceptually easy to understand, cannot be implemented in everyday measurements. For this reason, many methods have been developed to extract this important electrical parameter for MOSFET and other novel devices, and comparison is made for the techniques that are tester-friendly in this work.
The extraction methods for VT presented in this study include: extrapolation from point of maximum slope in Id-Vg curve, extrapolation of Id/√gm-Vg curve in the linear region, extrapolation of subthreshold slope and pre-defined current, gm/Id method with its maximum derivative to Vg, and gm/Id method with the equality of diffusion current and drift current. The extraction results are compared for CMOS and LDMOS devices in 180 nm technology node to see if they agree with each other. The goal is to recommend an extraction method that reports threshold voltage faithfully while taking the least amount of time.