In this thesis, high density plasma chemical vapor deposition (HDPCVD) is used to fabricate novel multiple quantum well structure of light emitting diodes (LEDs) and charge storaged layers of SONOS nonvolatile semiconductor memories (NVSMs). On the study of the light emitting diodes (LEDs) technology, wide band gap hydrogenated amorphous silicon carbide and porous silicon carbide has blue or green luminescence are currently being investigated for applications in optoelectronic devices. However, due to the indirect band gap character, the quantum efficiency of these LEDs is very low. In our experiment, we fabricate 5-periods hydrogenated amorphous silicon carbide multiple quantum well structure to enhance the luminescence efficiency. In our study, there are some following notable features: (1) The a-SixC1-x multiple quantum well structure prepared by high density plasma chemical vapor deposition and it shows visible photoluminescence at room temperature. (2) After fluorine ions implantation and thermal annealing, The PL energy of a-SixC1-x multiple quantum well shift to high energy. (3) The PL intensity of SiO2-barrier SixC1-x multiple quantum well is larger than SiNx-barrier. (4) The film adheres well to glass or Si wafer even at low deposition temperature, e.g. 200 0C by high density plasma chemical vapor deposition. On the study of the silicon-oxide-nitride-oxide-silicon (SONOS) nonvolatile semiconductor memories (NVSMs) technology, the SONOS is a multi-dielectric device consisting of an oxide-nitride-oxide (ONO) sandwich in which charge storage takes place in discrete traps in the silicon nitride layer. In addition to silicon nitride as the storage layer, we have studied the oxide/SiC:O/oxide sandwiched structures and thermal oxidation of SiC layer as a storage layer by HDPCVD processes. In our study, there are some following notable features: (1) From the capacitance-voltage and current-voltage characteristics of oxygen-incorporated silicon carbide with different oxygen content, it is observed that the memory window is decreased with increasing the oxygen content. By controlling the oxygen content, a higher breakdown voltage can be achieved. (2) In the study of the oxidation of SiC, it is found that low temperature (800 ¢J) oxidized SiC shows a larger memory window than that of the high temperature (925 ¢J) oxidized SiC by high density plasma chemical vapor deposition.