New approaches to in-situ heating in FIB/SEM systems

Abstract

Over last decades significant effort has been made on in-situ heating experiments inside SEM and FIB/SEM chambers. Traditional way is to use low vacuum environment in the entire chamber. Although this valuable approach brings various undeniable advantages, new state of the art experiments coincide with new requirements, such as rapid changes in temperature, high-vacuum operation to maximize experiment cleanliness, ultra-high resolution SEM imaging and on top of it adaptable geometry in order to investigate sample's crystallography and composition changes using EBSD and EDS detectors. In this contribution we introduce an integration of two new modules fulfilling these requirements by allowing in-situ heating in FIB/SEM systems under high vacuum conditions. Moreover, heating in high vacuum combined with injection of selected gases was also proven capable of providing sample surfaceThe module choice essentially depends on the sample size and the type of analysis required. For millimeter-sized samples, a bulk heating stage can be selected, which allows a heating rate of unit degrees per second for heating up to 1000°C. The heating stage is made of materials with negligible outgassing that assures experiment cleanness and can also provide high vacuum environment arround the heated sample with SEM chamber pressure in the order of 10-5 Pa. In-situ observation of microstructure evolution can be achieved by standard SEM detectors collecting SE and BSE signal passing through a user replaceable heat shield, which protects sensitive parts in SEM chamber from overheating. In addition, geometry of a dedicated heat shield permits EBSD mapping as well as EDS analysis of a heated sample placed on this heating stage. However, quality of the EDS and EBSD data is influenced by infrared radiation interference at temperatures above 600°C. This background can be reduced to minimum by employing a microheatingplate device.A novel microheatingplate device based on microelectromechanical systems (MEMS) technology provides a maximum temperature of 1200°C and a very high heating/cooling rate in the order of 10 5 degrees per second [3]. This MEMS chip is able to support nano-scale to sub-millimeter-sized samples (samples with dimensions in tens of µm are typically used). In-situ imaging of samples placed on the MEMS chip during heating can be obtained using all types of detectors [4] including STEM, EBSD and EDS. The localised heating and small thermal mass capacity bear indespensible merits such as high uniformity of the heating area, high stability even during operations above 1000°C, site specification and minor sample displacement and drift stablilization. Chunk samples (typically metallic samples for Materials Science research) can be first fabricated using FIB milling in the bulk, then in-situ lifted out, welded on the MEMS chip and optionally the sample surface can be cleaned with low kV ions. We present in Figure 2 EBSD results of microstructure evolution of a slightly deformed Ti6Al4V chunk sample obtained during in-situ heating at ...

The 3D Controllable Fabrication of Nanomaterials with FIB-SEM Synchronization Technology

“…In situ performance measurements can also be achieved by combining FIB-SEM with other attachments to fully understand and master the properties of nanomaterials. Micro heating plate devices can provide a stable and controllable environment for investigating materials at different temperatures, allowing for in situ observations of the thermal behavior, phase transformations, and crystallography and composition changes [71]. High density and uniformity in material preparations such as metals, ceramics, and composite The traditional preparation methods for bulk TEM samples are mechanical thinning, electrolytic polishing, and the ion milling technique [15], and their low success rate limits the application of TEM.…”

Direct Real Time Microstructure Evolution Observation of Ti-6Al-4V Alloy by In-Situ EBSD during Cycling Heating and Cooling at Elevated Temperatures using heater in SEM/FIB Systems

“…However, none of the previous work has achieved direct real time observation of the microstructure evolution of Ti-6Al-4V alloy at desired elevated temperatures (above β transus temperature approximately 995°C) due to technical limitations. Nevertheless, state-of-the-art microelectromechanical system (MEMS)-based micro heating device (µHeater) brings unique opportunities for convenient, fast and reliable in-situ heating (rapid heating/cooling rate in the order of 10 4 K per second up to 1200°C) under high vacuum conditions in SEM/FIB systems [2] and is compatible with all types of detectors such as EBSD, EDS and STEM [3].…”

Latest Developments in Environmental SEM Systems

“…The second heater type is the conventional ESEM heating stage, which allows sample temperatures up to 1400°C and reactions with the gas that is fed into the chamber. Finally, the so-called µHeater [6] heats a 100 µm diameter area up to 1200°C in less than 0.1 second. These extreme ramp rates (>10 4 °C/second) come with very minimal sample drift, allowing studies of nanoparticles in conditions previously not accessible.…”