Semi-automatic vacuum waferprober system

点击翻译按钮获取中文摘要

Nanoelectronic devices based on novel two-dimensional (2D) materials are increasingly fabricated with scalable manufacturing methods on wafer scale. The Chair of Electronic Devices (ELD) is actively researching 2D materials, which are integrated into devices with scalable processes over large areas up to 200 mm wafer size. Optimizing the growth and integration process of these 2D materials requires that devices and test structures can be characterized quickly and reliably over the entire wafer area. Characterization in vacuum is also important, since damage-free deposition of passivation layers is currently still difficult and the passivation often also influences the material and device properties. Therefore, we need a semi-automated vacuum wafer prober system for electrical characterization of unencapsulated 2D material devices, where adsorbates can be effectively removed by vacuum annealing up to 300 °C without oxidizing the 2D materials. This requires a high vacuum of <10e4 mbar (better in the 10e5 mbar range). Characterization of unencapsulated devices also allows growth and integration processes to be verified as quickly as possible with a number of minimal process steps, as each process step increases the risk of process-induced variability, damage, or contamination. Thus, time-efficient loops between growth/integration and characterization can be created to effectively and successively improve material and device parameters. The results are then immediately statistically meaningful by a semi-automatic measurement, in particular to analyze spatial variation on the wafer surface. We plan to equip the vacuum wafer prober with measuring devices for direct current (DC), high frequency (HF), capacitance (CV) and pulse measurements, so that the requirements of various types of devices are met, such as (high frequency) transistors, memristive devices or sensors for which we have various ongoing and planned projects. Many of these projects also aim at a large area realization (up to 200 mm wafer) e.g. in form of arrays of devices. Especially the memristive devices, which are to be fabricated in large scale arrays, are very much influenced in their switching behavior by the ambient atmosphere and a measurement under vacuum allows a reliable characterization under humidity free conditions, similar to the final application. At the RWTH Aachen site, there is currently no semi-automatic wafer prober that also offers this so important vacuum function (+ coupling with bakeout function up to 300 °C) and additionally has the possibility to perform measurements at DC, RF, CV or with pulses.