Dynamic Studies of Semiconductor Growth Processes Using In Situ Electron Microscopy
- PDF / 266,459 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 81 Downloads / 167 Views
Dynamic Studies
of Semiconductor Growth Processes Using In Situ Electron Microscopy Frances M. Ross
The following is an edited transcript from the 2000 MRS Outstanding Young Investigator presentation given by Frances M. Ross at the 2000 Materials Research Society Spring Meeting in San Francisco. Ross was cited for her “innovative and powerful experimental studies, based upon development of novel in situ electron microscopy techniques, that have provided fundamental new understanding of nucleation, growth, oxidation, and etching processes in a wide range of materials systems.” A Webcast of Ross’ presentation in Real Media format can be viewed via the MRS Web site, www.mrs.org/multimedia/spring2000/.
Introduction We have heard a lot about the exciting new materials being used in microelectronics, and I would like to describe some experiments making use of in situ electron microscopy to try to understand the mechanisms of the reactions that these materials undergo during deposition and processing. I will discuss experiments in which we carry out one of these reactions within an electron microscope and record the effect on the specimen in real time. We then use measurements from the recordings to analyze the reaction mechanism in a quantitative way. In this article, I will cover two types of experiments. First, I will describe experiments in which we examine the motion of surface and interface steps during reactions, and I will discuss how that information allows us to determine reaction mechanisms. In this context, I will consider silicon oxidation and silicide formation. In the second type of experiment, we look at how surface
94
morphology changes during reactions. In particular, we will try to understand the growth mechanism of “quantum dots,” which are becoming important for some novel microelectronic applications. After discussing these results, I will describe our attempts to extend the technique of in situ electron microscopy to look at systems other than the solid–solid or gas–solid interface.
In Situ Microscopy of Semiconductor Growth Processes Electron microscopy is an extremely versatile technique. We can optimize the imaging conditions to visualize, for example, grain boundaries, surface or interface steps, dislocations, strain fields, or surface features such as facets on island structures. While the microscope provides wonderful still images, it is even more exciting to observe these images changing while performing a reaction. This approach is generally referred to as in situ microscopy. We usually have to modify the microscope to carry out the reaction of interest, whether it is oxidation, deposition, or a heating or straining process, and we record the results with the electron beam continuously imaging the specimen. In many of the experiments, ultrahigh vacuum (UHV) is essential for forming a clean surface, for observing oxygen-sensitive processes, and for carrying out growth from the gas phase. Figure 1 shows two types of UHV electron microscopes. In the transmission electron microscope (TEM)
Data Loading...
