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

该资助将为近紫外、近场扫描光学显微镜系统的开发提供部分支持，该系统使用探针作为光电子收集器，在三维空间中具有~10-50纳米分辨率。探头的电压偏置将用于电压辅助光电发射，并且通过提供靠近表面的金属探头孔径的独特几何形状，电压偏置可以驱动半导体内部的场。后一种能力允许测量局部掺杂剂密度。受该仪器影响的材料系统包括：1)样品体积接近102立方厘米的材料识别。这解决了扫描探针显微镜长期存在的弱点-未知样品的材料鉴定困难和/或缓慢。该仪器将加强对空气中颗粒物的持续研究。2)环境条件下半导体的单掺杂成像。计数掺杂原子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此类研究。3)二维高分辨率掺杂物剖面。未来几代设备需要在10-50纳米分辨率水平上对掺杂物轮廓进行成像计量。没有多少技术可以希望成功地执行这种映射。该仪器为此类测量开辟了一个独特的场所，并将影响硅和氮化镓的设备研究。半导体表面的钝化在光电器件中是非常重要的。该仪器将以高分辨率查明钝化过程中的缺陷，以便确定其性质并采取措施纠正过程。目前，在宽带隙系统的研究中需要这样的仪器。5)教育机会来自对相关学生的培训以及在先进的教学实验室环境中使用仪器。后者将通过其独特的可变几何形状来阐明金属-绝缘体-半导体器件行为中的材料效应，该几何形状允许空气中下降的电压与半导体中下降的电压的比值变化。它也将在本课程中用于研究电压辅助光发射。该系统的开发将大大提高学生的研究能力和受教育的机会。

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.