Threshold voltage (VT)control of sub-0.25 μm processes using mercury gate MOS capacitors

MOSFET threshold voltage (VT) is the most important parameter governing sub-0.25 μm MOS device operation. Critical device performance issues such as speed, off state current and active power depend on VT (1). The primary components that influence VT are oxide thickness (Wox), oxide charge (Qox), interface trap charge (Qit), and channel dopant profile. Although conventional based CV methods have led many to believe that CV cannot be used for ultra-thin oxides, accurate methods for measuring VT and its components using both a hard probe and a high repeatability mercury probe are described in this paper.