Mackenzie David M A, Kalhauge Kristoffer G, Whelan Patrick R, Østergaard Frederik W, Pasternak Iwona, Strupinski Wlodek, Bøggild Peter, Jepsen Peter U, Petersen Dirch H
Center for Nanostructured Graphene (CNG), Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark. Department of Electronics and Nanoengineering, Aalto University, PO Box 13500, FI-00076 Aalto, Finland.
Nanotechnology. 2020 May 29;31(22):225709. doi: 10.1088/1361-6528/ab7677. Epub 2020 Mar 13.
Micro four-point probes (M4PP) provide rapid and automated lithography-free transport properties of planar surfaces including two-dimensional materials. We perform sheet conductance wafer maps of graphene directly grown on a 100 mm diameter SiC wafer using a multiplexed seven-point probe with minor additional measurement time compared to a four-point probe. Comparing the results of three subprobes we find that compared to a single-probe result, our measurement yield increases from 72%-84% to 97%. The additional data allows for correlation analysis between adjacent subprobes, that must measure the same values in case the sample is uniform on the scale of the electrode pitch. We observe that the relative difference in measured sheet conductance between two adjacent subprobes increase in the transition between large and low conductance regions. We mapped sheet conductance of graphene as it changed over several weeks. Terahertz time-domain spectroscopy conductivity maps both before and after M4PP mapping showed no significant change due to M4PP measurement, with both methods showing the same qualitative changes over time.
微四点探针（M4PP）可快速、自动地测量包括二维材料在内的平面表面的输运特性，且无需光刻。我们使用多路复用七点探针，在直径100毫米的碳化硅晶圆上直接生长的石墨烯上进行薄层电导晶圆图绘制，与四点探针相比，额外测量时间较短。比较三个子探针的结果，我们发现与单探针结果相比，我们的测量合格率从72%-84%提高到了97%。额外的数据允许对相邻子探针之间进行相关性分析，在样品在电极间距尺度上均匀的情况下，相邻子探针必须测量相同的值。我们观察到，在高电导区域和低电导区域之间的过渡中，两个相邻子探针测量的薄层电导的相对差异会增加。我们绘制了石墨烯在几周内变化的薄层电导图。太赫兹时域光谱电导率图在M4PP映射前后均显示，由于M4PP测量没有显著变化，两种方法在随时间的定性变化上是相同的。
