On-chip sampling sensors for high frequency signals measurement: evolution and improvements

Due to increasing speed and complexity, integrated circuits (ICs) are faced with severe parasitic problems: signal glitch, supply, crosstalk induced delay, substrate coupling. Various measurement techniques have been developed in order to observe these effects. Off-chip methodologies such as E-beam sampling, direct probing or S-parameters, allow to probe some parasitic phenomena, but they have strong limitations in term of bandwidth, invasive probes, complex setup or cost. In this paper, an overview of different on-chip measurement systems is presented. An on-chip sampling technique is detailed and we describe the applications for which this sensor has succeeded to provide accurate measurements. Sensor performances are compared for four CMOS technologies (0.7μm, 0.35μm, 0.18μm and 90nm). In the last part, we present an improved sensor which measures all parasitic phenomena in the full supply range.