The effect of ambient gas in the sealing process on the field emitter array (FEA) was analyzed. The FEAs which consist of tips with 1 mu m height, 1.1 mu m width, and gate holes with I mu m diameter, were fabricated and these array samples were baked in Ar, N-2, and vacuum with the same temperature condition of 470 degrees C for 24 min. After this treatment, the measurements of the electron emission current were carried out for each sample and it was found that there was no difference between before and after baking in each sample. Also, the pieces of glass coated with Mo film of 500 Angstrom were baked in the same condition with the arrays. Auger electron spectroscopy (AES) depth profiling and x-ray photoelectron spectroscopy analysis were performed with these samples. From AES analysis, it was found that the same depth of Mo oxide layer was formed an the surfaces of every sample.