A simple method to make cross sectional TEM samples of Si and GaAs semiconductor devices at specific device locations using electron beam (e-beam) lithography and reactive ion etching is described. The basic idea of this technique is to form pillar or line type patterns thin enough to be transparent to electron beams used in transmission electron microscopy. Since the entire process is conducted in the semiconductor fabrication facility, reliable samples were efficiently obtained within a short time without mechanical polishing or ion milling. High Resolution Electron Microscopy (HREM) images of SiGe and GaAs multilayer structures were obtained by this method. Using the alignment function of the e-beam lithography system, cross sectional TEM samples at specific locations of MOS transistors were obtained. The samples were thin enough to obtain HREM images of atomic level defects in the device.

The issue of specimen contamination becomes more important at a rate proportional to the use of high-brightness electron source Transmission Electron Microscopes (TMM). The trend in the transmission electron microscopy of materials science specimens is to use higher-voltage microscopes incorporating field emission gun technology [1]. These FEG TEMs combine smaller electron probes with increased beam current, allowing high resolution specimen imaging and enhanced analytical data collection. This is of particular importance for semiconductor specimens which demand fine-probe microanalyis.

A new procedure is developed for making TEM specimens of thin film devices. In this procedure the sample is flatly polished to an overall “ion-mill-ready” thickness so that any point in the 2-D sample plane can be thinned to an electron-transparent thickness by subsequent ionmilling. Using this procedure small regions of interest can be easily reached in both cross-section and plan-view samples. This is specially useful in device studies. Applications of this procedure to the study of superconductor devices yield good results. This procedure, using commercially available equipment and relatively cheap materials, is simple and easy to realize.

The success of in-situ transmission electron microscopy experimentation is often dictated by proper specimen preparation. We report here a novel technique permitting the production of crosssectioned tensile specimens of multilayered films for in-situ deformation studies. Of primary importance in the development of this technique is the production of an electron transparent microgauge section using focused ion beam technology. This micro-gauge section predetermines the position at which plastic deformation is initiated; crack nucleation, growth and failure are then subsequently observed.

It is very difficult to prepare cross-sectional TEM samples for phase-change optical disks by conventional argon ion milling because of the difference of ion milling rates between multilayers and the polymer substrate. We have been successful in preparing samples of those optical disks by ion milling method with dissolution of the polymer substrate in advance. The cross-sectional structure was observed more clearly in this method rather than in ultramicrotome method.

In-situ transmission electron microscopy (TEM) has been used to characterize the solidphase epitaxial growth of amorphized GaAs at a temperature of 260°C. To maximize heat transfer from the heated holder to the sample and minimize electron-irradiation induced artifacts, non-conventional methodologies were utilized for the preparation of cross-sectional samples. GaAs (3xI) mm rectangular slabs were cut then glued face-to-face to a size of (6x3) mm stack by maintaining the TEM region at the center. This stack was subsequently polished to a thickness of ~ 200 ýtm. A 3 mm disc was then cut from it using a Gatan ultrasonic cutter. The disc was polished and dimpled on both sides to a thickness of ~15 mimT.h is was ion-beam milled at liquid nitrogen temperature to an electron-transparent layer. From a comparison of in-situ and ex-situ measurements of the recrystallization rate, the actual sample temperature during in-situ characterization was estimated to deviate by ≤ 20°C from that of the heated holder. The influence of electron-irradiated was found to be negligible by comparing the recrystallization rate and microstructure of irradiated and unirradiated regions of comparable thickness. Similarly, the influence of “thin-foil effect” was found to be negligible by comparing the recrystallization rate and microstructure of thick and thin regions, the former determined after the removal of the sample from the microscope and further ion-beam milling of tens of microns of material. In conclusion, the potential influence of artifacts during in-situ TEM can be eliminated by the appropriate choice of sample preparation procedures.

The construction and performance of an improved ion milling instrument are described. The updated instrument is based upon an earlier version fixed low angle ion milling system. The updated system employs two improved guns having the ability of independent variable milling angle adjustment, while operating at high voltage in the vacuum system. The milling rate of these ion guns is typically ≈ 90μm/hr/gun pair for copper at 5keV and 10°. Designed to compliment the variable angle ion gun is a new specimen holder which permits low angle double sided milling. The combination of these two features offers numerous single or double sided milling conditions to facilitate the production of higher quality TEM specimens in less time. The range of ion gun angles encompassed is 0° to 10° for single-sided milling and 0° to ± 10° for double-sided milling. The instrument also incorporates an electronic mechanism to generate directional sector milling which benefits primarily the production of cross sectional TEM specimens and heat sensitive materials since the ion guns are turned off for a portion of time during each revolution. Another new feature of the instrument is chemical ion milling which facilitates the preparation of certain compound semiconductors. The ability of this improved ion milling instrument for rapid ion polishing and improved specimen quality is demonstrated by a number of TEM images of metals, ceramics and semiconductors.