A compositional profile of a native oxide LPCVD MNOS structure has been obtained by x‐ray photoelectron spectroscopy used in conjunction with a stopped‐flow chemical etching procedure. A depth resolution of 5–10Å was achieved. Stoichiometric was found in the bulk with about 0.4 atomic percent (a/o) oxygen impurity. In contrast to profiles completed by other techniques, was found intact at the interface; complete conversion of oxide to oxynitride during LPCVD did not occur. The oxide/nitride interface is best described as sharp; the oxygen concentration drops by 80% in less than 8Å. There is also a diffuse oxynitride gradient extending into the film, but the oxygen concentration in this region is quite low. Evidence was also found for an 8Å layer containing excess bonds to silicon between the oxide and nitride layers. Possible charge trap structures that might limit device performance are discussed along with processing suggestions aimed at minimizing the formation of traps.