GAS INLET ~

The manufacture ofdevices incorporating very thin gate oxides requires the use of lower ion bombardment ener-gies than those in current use in reactive ion etch (RIE) systems (1). In order to maintain a useful etch rate at low ion energy it is necessary to decouple intense plasma and active species generation from their application on a wafer surface. For this study we have used a commercial distrib-uted electron cyclotron resonance (DECR) plasma appa-ratus, the Electrotech MPM 390 system. This consists of a cylindrical plasma chamber with eight antenna rods (mi-crowave applicators) fed with 2.45 GHz microwave power at the periphery (Fig. 1). A permanent magnet system out-side the chamber creates the field for ECR plasma genera