No abstract

The crystallization of low pressure chemical vapor deposition amorphous silicon films was studied by transmission electron microscope observations. The results demonstrate the interdependence of the silicon deposition rate, the incubation time for nucleation, and the crystalline growth rate. At temperatures below 600 °C the deposited films are amorphous, but partial crystallization can occur the deposition time is longer than the incubation time. Crystallization occurs through an epitaxial-like growth from nucleates near or at the substrate interface; the crystalline phase will reach the depositing interface for thick films if the growth rate exceeds the deposition rate. The crystallized fraction of the deposited layer can be controlled by regulating the deposition temperature and rate and by in situ addition of dopant impurities. At temperature higher than 600 °C the deposited films are polycrystalline and columnar in structure. The surface texture is much smoother for films whose surfaces are amorphous.

LANGMUIR are 100-500 eV. For SiO2 etch rates vary essentially in proportion to ion densities with all the different plasmas. In addition, there is evidence for a dependence of the etch rate on the ion energy. For Si in CF4-O2 plasmas of different composition, the anisotropic part of the etch rate also parallels the ion density. From an estimate of the ion flux ~o the substrate we are able to determine etch rates per ion in reactive sputter etching. These turn out to be comparable to, possibly even larger than, those in reactive ion beam etching, although in reactive sputter etching ion energies are much smaller.

No abstract

The oxidation characteristics and the electrical conductivity and breakdown of thin oxides grown on phosphorus in situ doped polysilicon are reported. Breakdown fields of 8 mV/cm and leakage currents as low as 5 • 10 -~ A/cm 2 at 3.5 MV/cm were measured for 400-to 1200A oxides grown thermally at 1000~ in dry O~ on phosphorus in situ doped films deposited at 600~ The oxides grown on the 600~ polysilicon films are superior to the oxides grown on the 640~ polysilicon films. The high breakdown fields and low leakage currents are related to the film structure and surface morphology as revealed by SEM and TEM micrographs.