Radiation damage in silicon dioxide films exposed to reactive ion etching
The enhanced electron-trapping characteristics and the location of this trapped charge in an SiO/sub 2/ layer exposed to either CF/sub 4/, O/sub 2/, or Ar plasmas in a reactive ion etching (RIE) system are reported. Capacitance-voltage (C-V) and photocurrent-voltage (photo I-V) techniques were used to monitor charge trapping and location after the samples were incorporated in metal-oxide-semiconductor (MOS) capacitors. Using a CF/sub 4/ plasma which etches SiO/sub 2/, trapping sites caused by penetrating radiation were observed. These traps were removed by annealing at temperatures > or =600 /sup 0/C for 30 min in N/sub 2/ prior to metallization. These bulk SiO/sub 2/ trapping sites showed no strong dependence on whether the samples were placed on the anode or cathode in the RIE chamber, implying no preferred directionality in the photons which are believed to generate them. With an O/sub 2/ or an Ar plasma which does not etch SiO/sub 2/, an additional trapping layer within about 100 A of the exposed SiO/sub 2/ surface caused by penetration of energetic ions (< or =400 eV) was detected. Trapping in this layer was greatly reduced by a 1000 /sup 0/C anneal in N/sub 2/ for 30 min, and almost entirely removed by a buffered HF dip which etched about 100 A of SiO/sub 2/. Samples placed on the anode (ground plane) of the RIE system which would see energetic secondary electrons, but only relatively low-energy ions (approximately 35 eV), also had electron-trapping sites near the exposed surface; however, the trapping in this layer was greatly reduced compared with samples placed on the cathode.
- Research Organization:
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598
- OSTI ID:
- 6003666
- Journal Information:
- J. Appl. Phys.; (United States), Vol. 50:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SILICON OXIDES
PHYSICAL RADIATION EFFECTS
CAPACITORS
CHARGE CARRIERS
ELECTRONS
ETCHING
FILMS
ION COLLISIONS
PLASMA
TRAPS
CHALCOGENIDES
COLLISIONS
ELECTRICAL EQUIPMENT
ELEMENTARY PARTICLES
EQUIPMENT
FERMIONS
LEPTONS
OXIDES
OXYGEN COMPOUNDS
RADIATION EFFECTS
SILICON COMPOUNDS
SURFACE FINISHING
360206* - Ceramics
Cermets
& Refractories- Radiation Effects