Scanning Spreading Resistance Microscopy and Its Application to Passive and Active Semiconductor Device Characterization

Scanning Spreading Resistance Microscopy (SSRM) is a surface analysis technique offering unique qualities. The method combines outstanding spatial resolution and a high dynamic range of the obtained electrical signal. Therefore, it is an excellent candidate for two dimensional characterization of the free carrier distribution, closely related to semiconductor dopant distribution. The dopant distribution defines the functionality of every semiconductor device and therefore, its understanding is of major importance in semiconductor manufacturing. Within this work the method is discussed in detail. Improvements are presented in certain aspects of sample preparation and data acquisition. The positive aspects and advantages of SSRM are demonstrated by its employment to selected application cases. For the characterization of actively driven semiconductor devices a new method is introduced within this work. Scanning Dynamic Voltage Spreading Resistance Microscopy (SDVSRM) acquires the local effective sample surface voltage in a first pass. The second pass performs the actual SSRM measurement, while maintaining the internal voltage differences at the respective terminals. The new technique enables superior insights into semiconductor device performance, as free carrier distribution can be visualized while at the same time driving voltages are applied to the device.