High temperature specimen stage and detector for an environmental scanning electron microscope

摘要

An environmental scanning electron microscope is provided with means to maintain a specimen at a temperature approximately 1500 DEG C. In this microscope, a specimen chamber (22) maintains the specimen (24) enveloped in a gas in registration with a final pressure limiting aperture of the objective lens assembly. The specimen chamber includes a specimen stage (0) having a sample platform (49) for supporting the specimen under examination at a first vertical height and a specimen heating assembly (56) which includes a non-inductively wound heater coil (58) which is positioned closely adjacent to the sample platform and extends to a second height which is significantly above the first vertical height so that the top of the specimen is maintained at a high temperature. In this microscope, a heat shield assembly (68) is positioned above the specimen heating assembly in the specimen chamber to avoid radiant heat loss and which has an adjustable bias voltage (80) applied thereto to accelerate secondary electrons through its central opening to be collected by an electron detector (136). In order to enhance image quality, the final aperture and electron detector are biased at different voltages with the bias to said aperture floated to provide automatic compensation. A specimen moving assembly (210) is also provided to move the specimen stage with respect to the heat shield assembly. <IMAGE>