Studies of the Effects of Side Walls on VLSI Semiconductor Devices.
Abstract
Properties and effects of side walls in very large scale integrated (VLSI) devices are explored and studied. Many side wall related properties, such as damage on side walls caused by reactive ion etching (RIE) and ion implantation, impurity diffusion in from side walls, segregation of atoms to side walls, and side wall heat absorption, are investigated and found to be significant. Properties of the side walls are compared to those of a horizontal surface. The wake potential of a fast charged particle is derived for an atomic system using a first-order quantum -mechanical perturbation theory. The atomic Coulomb excitation cross sections of the target atoms by this wake potential are then derived and found to be large. Numerical results for a model system of condensed atomic hydrogen show that the wake potential is important and should be included in calculating the atomic Coulomb excitation cross sections in condensed matter. The wake potential along the path of a fast charged particle is also calculated for the case of hydrogen 1s 2s and 2p transitions without a cutoff parameter. A computer program has been written to simulate the RBS spectrum from stripes that are similar to VLSI device components. The simulation fits experimental data well and can be used to determine diffusion in horizontal directions. It also provides an accurate way of measuring angle of the stripe side walls. The charged particle stopping power change due to the transition to the superconducting state is estimated and measured. The change of stopping power depends on the energy gap of the superconductor, and may be measurable for low energy charged particles. The relative stopping power difference of a 1 MeV proton between the superconducting and normal states of polycrystalline YBa_2 Cu_3O_7 at 77K was measured to be 0.06 +/- 0.14%. The hydrogen concentration in CVD P glass, CVD TEOS oxide, phosphorus doped TEOS oxide, plasma enhanced CVD oxide, low pressure CVD nitride and plasma enhanced nitride are studied. Hydrogen redistribution during furnace and rapid thermal annealing (RTA), room temperature diffusion, and hydrogen diffusion from nitride layer into oxide layer are also studied.
- Publication:
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Ph.D. Thesis
- Pub Date:
- August 1990
- Bibcode:
- 1990PhDT........53G
- Keywords:
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- Physics: Condensed Matter; Engineering: Electronics and Electrical