Advanced Optical Diagnostics of High Density Etching Plasmas
Final rept. 15 Aug 1994-14 Aug 1998
NEBRASKA UNIV LINCOLN HYDRODYNAMICS LAB
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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 AlGaAsGaAs heterostructure used to form the emitterbase 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.
- Electrical and Electronic Equipment
- Test Facilities, Equipment and Methods
- Plasma Physics and Magnetohydrodynamics