Investigation Of Esem Environment And In-Situ Observation And Analysis

In this thesis, we focused on the electron scattering effect and charge environment in the ESEM. Several applied technologies about in-situ analyzing in the ESEM were studied.The interactions among the electron, gas and the specimen were studied at first in this thesis. We studied the electron scattering effect in the ESEM by means of computer simulation, calculation and experimentation. The charge environment of ESEM chamber was measured also. The process of the electron scattering by gas molecules was simulated. The method and program were given as well as the graphs of electron distribution. The calculation revealed that the scatter radio and radius of electron become larger with the increase of the pressure, and become smaller at high temperature. Calculation, simulation and the experimental results coincide with each other. The results showed that in the commonly used pressure range of 130~300Pa in ESEM, electron scattering is in a radius of 100μm, and the effect of electron scattering within the range of 1000μm.A measuring system of a pA-meter with high sensitivity was built in ESEM to measure the specimen currents (ISP) of a Faraday-cup and three specimens, i.e., Cu-Zn alloy, Si and Al2O3 single crystals. ISP values indicated charge environments of ESEM chamber, which were controlled by the electron current and the ion flow. ISP values of the Faraday-cup indicated charge environments controlled by the primary electron and the ion, whereas ISP values of the specimens indicated charge environments controlled by the primary electrons, signal electrons and the ion. Ionization efficiency and saturation, as well as the electron scattering by gas molecules under various operating and environmental conditions could be determined by ISP values in ESEM.The in-situ heating stage and electrical device were designed and manufactured, to attach the micro-injection system and micro-current measuring system based on the ESEM. So combined environmental conditions for in situ dynamic reaction and observation was built by regulating indoor environmental pressure, humidity, and other parameters of the atmosphere. On this basis, this paper, three applications of the ESEM situ dynamic analysis were studied.Comprehensive Utilization of gas-injection devices and heating devices, optimizing the ESEM chamber environment parameters, enables ESEM to become an experimental installation of in-situ growth of ZnO nanowires. Experiments show that the morphology of ZnO is closely linked with gas supersaturation and substrate temperature. Uniform size ZnO nanowires can grow at low temperature, low-pressure environment in the ESEM by using Micro-injected devices. This simultaneously allows ETD secondary electron detector can work normally in high vacuum mode. A clear observation of in situ growth process can be obtained. ESEM become a dynamic research micro-experiment platform to study the in-situ growth of nanomaterials.In situ observing and analyzing of the Al interconnection line electromigration failure process can be done by means of accelerated failure method in transistor. In experiments, the growth state of hills proved that the effects of return. According to the in situ growth time and size of single whisker, Calculating the growth radio v = 33.7nm/min, the actual t ion flux density J = 1.53×10-7 g /cm2 ? sec, and the diffusion coefficient Deff = 2.5×10-10cm2/sec.Using ESEM heating device and micro-current measuring system, we studied a new phenomenon--the charging effect of the type of ceramic samples (Al2O3 and YAG) can be eliminated when they were heated. For polycrystalline alumina sample, with the rise of temperature, the charging phenomenon weakened gradually. Sample Current ISP becomes positive totally and tended to stabilize, the corresponding electron emission coefficient (η+δ) is gradually increasing. The charging effect is eliminated completely at 300℃. The phenomenon that the charging effect can be eliminated is closely correlated with the raise of insulator surface conductivity when it is heated, and introduction of the defect (impurity) energy level in the wide-band insulation materials energy level.A micro-experiment platform of dynamic and in-situ observation can be built, with the ESEM equipped experimental devices of the integrated field, to study in situ growth and dynamic change of the material with the resolution of micron-micron resolution.