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

研制了一种新型的W悬臂扫描电容显微镜，其中设计了一种新的光反馈系统。通过相当程度地抑制杂散电容引起的噪声，对电容变化的高灵敏度检测成为可能，从而使电容低至1af。电容测量的横向分辨率可达2Onm。这些功能是SCaMs中最好的，可以直接测量CV。可以同时测量dC/dV。我们通过这个新颖的骗局实现了以下目标：(1)澄清dC/dV信号的物理含义。我们已经指出，dC/dV信号非常依赖于偏置条件和调制电压，因此它的解释需要CV测量。(2)实验结果表明，该方法可用于表征亚微米栅极长度的MOS器件。借助器件的扫描电容图像，可以适当地使用dC/dV技术对电容的微小局部变化进行成像。(3)测量了横向pn结的局部CV特性，并利用器件模拟器对其特性进行了模拟。已经证明，将骗局与设备模拟相结合，可以表征迄今为止已经执行的局部电特性。

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.