Techniques for shadow mask deposition of nonplanar dielectric layers

In this investigation, we explore the deposition of nonplanar dielectric layers using laser micromachined shadow masks. Depositing dielectrics on semiconductors is advantageous for a variety of reasons. By finishing VCSELs or RC-LEDs with dielectric layers, expense and time can be avoided. The shadow masks were produced by laser micromachining on alumina and stainless steel. The top holes ranged from 10 μm to 150 μm in diameter. Deposition of SiO₂, Si₃N₄ or multilayer combinations of these materials was performed using plasma-enhanced chemical vapor deposition (PECVD) and sputtering through the shadow masks. The results from our study examine how the deposition method, deposited material and physical geometrical parameters of the shadow masks and their relative compositions influence the deposition rates and deposition patterns.