Advanced Optical Diagnostics of High Density Etching Plasmas
Abstract
The purpose of this work was to investigate the use of in-situ spectroscopic ellipsometry as a means to control the etching of III-V semiconductors and in particular an AlGaAs/GaAs heterostructure used to form the emitter/base junction of a heterojunction bipolar transistor (HBT) used in high frequency circuits employed in Air Force communications. The specific objective was to use in-situ SE to monitor the etching of the AlGaAs emitter layer and stop to within a few nanometers of the GaAs base layer. Toward this end, an Electron Cyclotron Resonance (ECR) microwave plasma system and custom built stainless steel bell jar were used to construct an etch tool. The ECR microwave plasma is a low pressure, high density plasma source capable of producing highly anisotropic etch profiles. The ellipsometer used was a J. A. Woollam Co. model M-44. The M-44 is a 44 wavelength ellipsometer operating in the visible region from approx. 400-800 nm.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2000
- Accession Number
- ADA386844
Entities
People
- N. J. Ianno
- P. F. Williams
Organizations
- University of Nebraska–Lincoln