Development of a Near-Field Scanning Photoemission Microscope for Materials Identification and Dopant Imaging and Student Training

这笔赠款将为开发一种近紫外线、近场扫描光学显微镜系统提供部分支持，该系统将使用该探测器作为三维分辨率为~10-50 nm的光电子的收集器。探头的电压偏置将用于电压辅助光电发射，通过金属探头孔靠近表面提供的独特几何结构，电压偏置可以驱动半导体内部的磁场。后一种能力允许测量局部掺杂密度。受该仪器影响的材料系统包括：1)样品体积接近102Nm~3的材料识别。这解决了扫描探针显微镜的一个长期弱点--对未知样品的材料识别困难和/或缓慢。该仪器将加强对空气中颗粒物的正在进行的研究。2)在环境条件下，半导体中的单掺杂成像。对掺杂原子进行计数可能是研究表面附近掺杂分布的最终方法。该仪器将允许在空气中对工业相关样品进行这样的研究。3)二维高分辨率掺杂剂分布。接下来的几代设备需要在10-50 nm分辨率水平上对掺杂剂轮廓进行成像计量。希望成功执行这种映射的技术并不多。该仪器为此类测量提供了一个独特的场所，并将影响对硅和氮化镓的器件研究。4)半导体表面的钝化在光电子器件中非常重要。该仪器将以高分辨率精确定位钝化过程中的缺陷，以便识别它们的性质并采取行动纠正工艺。目前，在宽带隙系统中的努力需要这种仪器。5)教育机会来自对参与的学生的培训和在先进的教学实验室环境中使用该仪器。后者将通过其独特的可变几何结构来阐明材料对金属-绝缘体-半导体器件行为的影响，该几何结构允许改变空气中下降的电压与半导体中下降的电压之比。该系统的开发将极大地提高学生的研究能力和教育机会。

This grant will provide partial support for the development of a near-ultraviolet, near-field-scanning-optical-microscope system using the probe as a collector of photoelectrons with ~10-50 nm resolution in three dimensions will be developed. Voltage biasing of the probe will be used for voltage-assisted photoemission and, through the unique geometry provided the metal probe aperture in close proximity to the surface, the voltage bias can drive a field internal to a semiconductor. The latter capability permits measurement of the local dopant density. Materials systems impacted by this instrument include:1) Materials identification in sample volumes approaching 102 nm3. This addresses a long-standing weakness of the scanning probe microscopes - that material identification of unknown samples is difficult and/or slow. The instrument will enhance ongoing studies of particulate matter from the air.2) Single dopant imaging in semiconductors under ambient conditions. Counting dopant atoms is perhaps the ultimate way to study dopant distributions near surfaces. This instrument will permit such studies in air, on industrially relevant samples.3) High-resolution dopant profiles in two dimensions. The next few generations of devices require imaging metrology of dopant profiles on the 10-50 nm resolution level. There are not many techniques that can hope to successfully perform such mapping. This instrument opens a unique venue to such measurements, and will impact device research on silicon and gallium nitride.4) Passivation of semiconductor surfaces is very important in optoelectronic devices. This instrument will pinpoint defects in the passivation at high resolution so that their nature can be identified and actions taken to correct the process. Currently, efforts in wide bandgap systems are in need of such instrumentation.5) Educational opportunities arise from the training of the students involved and from use of the instrument in an advanced teaching laboratory environment. The latter will elucidate the materials effects in the behavior of metal-insulator-semiconductor devices through its unique variable geometry that allows changes in the ratio of voltage dropped in air to that dropped in the semiconductor. It will also be used in the course to investigate voltage-assisted photoemission.%%%The development of this system will significantly enhance research capabilities and educational opportunities for students.