Comparison of dry etch chemistries for SiC

Document Type

Article

Publication Date

1-1-1997

Abstract

SiC has generally been plasma etched in polymer-forming chemistries such as CHF3/O2 or CF4/O2, often with addition of H2 to achieve acceptable surface morphologies. We find that under high ion density conditions gases such as SF6, NF3, IBr, and Cl2 produce smooth surfaces that are free of hydrogen passivation effects. Etch rates in excess of 1500 Å/min are achieved in electron cyclotron resonance (ECR) NF3 or Cl2/Ar discharges with low additional rf chuck powers (100-150 W); dc bias of -120 to -170 V. The rates are somewhat lower (factors of 2-4) with IBr and SF6 chemistries. Ion-induced damage is evident from Hall measurements for SiC exposed to rf powers >150 W (dc bias >-170 V) under ECR conditions and >250 W (dc bias >-275) under reactive ion etch conditions. Efforts to anneal damage at these higher powers reveals a major annealing stage is evident at ∼700 °C, with an activation energy of ∼3.4 eV, but there is significant damage remaining even after 1050 °C annealing. Hydrogen passivation is a problem only in p-type SiC, and is removed at similar temperatures to ion-induced damage by annealing at ∼700 °C under N2 ambients. This is strongly correlated with secondary ion mass spectrometry measurements on deuterated samples annealed at different temperatures. © 1997 American Vacuum Society.

Identifier

5844317505 (Scopus)

Publication Title

Journal of Vacuum Science and Technology A Vacuum Surfaces and Films

External Full Text Location

https://doi.org/10.1116/1.580726

ISSN

07342101

First Page

885

Last Page

889

Issue

3

Volume

15

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