A simple test structure for accurately monitoring channel doping variations in a MOSFET

A new test structure and measurement technique is described that allows improved monitoring of the integrated channel doping in MOSFETs that is the primary cause of statistical threshold voltage fluctuations. The methodology is physically based and has been applied successfully to a 0.8 /spl mu/m BiCMOS process. The advantages of this approach over the conventional method are clearly demonstrated. Results obtained from high volume testing are also presented.<
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