Research

PLASMA ETCHING OF NEW MATERIALS

Introduction

Hafnium oxide is replacing SiO2 as the dielectric layer below gate electrodes in complementary metal oxide semiconductor (CMOS) field effect transistors (FETs). We are investigating etching of this important material in boron trichloride plasmas, using a variety of diagnostic methods, including x-ray photoelectron spectroscopy (XPS). As shown below, etching in a BCl3 plasma removes the HfO2 layer, but leaves an undesirable boron residue on the underlying silicon substrate. We can successfully remove this layer with a subsequent hydrogen plasma cleaning process, as confirmed by XPS measurements such as those reproduced below.

 

Selected Publications

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