Development of nano-scale characterization technology for semicondutors and devices with scanning capacitance microscope

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A novel scanning capacitance microscoe has been developed with a W cantilever, in which a new optical feed-back system is invented. By considerably suppressing noise due to stray capacitance, high sensitive detection of capacitance variation has become possible, which enables a capacitance as low as 1 aF.The lateral resolution for capacitance measurements is as good as 2Onm. These features are the best among SCaMs which enables direct CV measurements. It is possible to measure dC/dV simultaneously. We have achieved the followings with this novel SCaM : (1) To clarify the physical meaning of dC/dV signals. We have indicated that the dC/dV signal is so dependent on the bias conditions and modulation voltage that its interpretation requires the CV measurements. (2) It is demonstrated that the SCaM can be used to characterize real MOS devices with submicron gate length. With a help of scanning capacitance image of the device, a dC/dV technique can be properly used to image even a slight local change in capacitance. (3) Local CV characteristics of a lateral p-n junction has been measured, while its characteristics have been simulated using a device simulator. It has been demonstrated that the combination of the SCaM with device simulation enable to characterize local electric properties which have hitherto been performed.