Method of forming an insulation structure and method of manufacturing a semiconductor device using the same

A method of forming an insulation structure, comprising:

• forming at least one oxide layer on an object by at least one oxidation process;
• and
• forming at least one layer having nitrogen from the at least one oxide layer by at least one nitration process,
• wherein forming the at least one oxide layer and forming the at least one layer having nitrogen includes:
• performing a first oxidation process to form a first preliminary oxide layer on the object by partially oxidizing the object, the first oxidation process including a radical oxidation process and the first preliminary oxide layer being formed in accordance with a reaction between a first oxygen radical generated by a direct plasma process and silicon included in the object,
• performing the nitration process to form a preliminary nitride layer from a lower portion of the first preliminary oxide layer on the object and a second preliminary oxide layer from the first preliminary oxide layer on the preliminary nitride layer, wherein the nitration process includes performing an annealing process using ammonia gas, and
• performing a second oxidation process using oxygen and hydrogen chloride gases to form a nitride layer, a lower oxide layer and an upper oxide layer sequentially on the object,
• wherein the nitride layer is formed from the preliminary nitride layer on the object, the lower oxide layer is formed from the second preliminary oxide layer on the nitride layer, and the upper oxide layer is formed from a portion of the second preliminary oxide layer on the lower oxide layer.