A dummy wafer structure and a method of forming the same are disclosed. The dummy wafer structure includes: a silicon substrate; a silicon nitride layer over the silicon substrate; and a silicon dioxide layer over the silicon nitride layer. The method includes: a first step of forming a silicon nitride layer over a silicon substrate so as to form a silicon-silicon nitride structure; and a second step of forming a silicon dioxide layer over the silicon-silicon nitride structure obtained in the first step so as to form a silicon-silicon nitride-silicon dioxide structure. Dummy wafers with this special structure are able to avoid deposition rate inconsistency in a polysilicon deposition process and are capable of avoiding conventional dummy wafers' adverse effect on deposit layer thicknesses of process wafers and hence providing the process wafers with deposit layers having a high inter-wafer uniformity.