Bilaycr SiNx/diamond films for X-ray lithography mask

In this research, an alternative fabrication process is proposed for SiN.v/diamond and diamond membranes. After diamond film deposition, SiN_x films were coated on both sides of the diamond film using the low-pressure chemical vapor deposition (LPCVD) process. The back side of the SiN_x film was selectively etched using the reactive ion etching (RIE) technique. The SiNx/diamond membrane was then obtained by etching the back side of the silicon wafer with KOH solution. The diamond membrane was finally achieved by etching the front side of the SiN_x film. It was found that the concentration of methane affects the quality, film stress and surface roughness of polycrystalline diamond films. These properties also influence the optical transmittancc of the membranes. Typically, it was found that bilayer SiN_x/diamond membranes exhibited a higher optical transmittancc than diamond membranes. It was also shown that samples with lower methane content (1.5%) possessed higher optical transmittance than those with higher methane content (2%). The optical transmittancc of the 51(1.5%) bilayer SiNx/diamond membrane was about 57% at a wavelength of 633nm and up to 66% at a wavelength of 800nm. The optical transmittancc of the bilayer SiN_x/diamond and diamond membranes increased by approximately 7% and 5% for 51(1.5%) since the quality of the diamond films improved after X-ray irradiation.