Etching Chemistry of III-V Semiconductors and the Development of Surface Roughness
Abstract
This research addresses the need for fundamental information concerning halogen etching of III-V semiconductors. The reactions of halogens with semiconductor surfaces are the fundamental chemical interactions in processes employed for device manufacture. In this work, the reactions of XeF2, Cl2 and I2 with III-V semiconductor surfaces were investigated with synchrotron-based soft x-ray photoelectron spectroscopy, low energy electron diffraction and scanning tunneling microscopy. Fluorine reaction grows films of group III fluorides, which can be used as dielectric materials. Chlorine is the most widely used halogen for dry etching, while iodine has been proposed for use as a "gentle" etchant. We found that, for all of the halogen reactions, the initial adsorption depends on the surface reconstruction, stoichiometry and condition. Some surfaces passivate, while others spontaneously etch at room temperature. The passivated surfaces are well-ordered and covered with approximately one monolayer of adsorbed halogen. The etched surfaces, on the other hand, are considerably rough and atomically disordered. A microscopic model is proposed which assumes that halogen atoms preferentially adsorb onto a group III atom if the surface is initially well-ordered. This microscopic model can explain why certain surfaces etch, while others form ordered overlayers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 13, 1998
- Accession Number
- ADA344525
Entities
People
- Jory A . Yarmoff
Organizations
- University of California, Riverside