A new self-aligned process for fabrication of microemitter arrays using selective etching of silicon

Field electron emitter arrays (FEAs) have been fabricated by a novel self-aligned process. In this process the crystal-orientation dependent (anisotropic) and doping density dependent etching characteristics of single crystal Si are fully utilized. The emitter is formed by depositing a material in a mold prepared by anisotropic etching and thermal oxidation of Si. The gate is made of highly boron doped single-crystal Si, which acts as the etching mask for the mold formation. Gate/emitter spacing is determined by well-controlled ion implantation and thermal diffusion processes. FEAs with WSi₂ emitters have been fabricated. The results demonstrate a small dispersion in gate/emitter spacing 3σ = 0.19 μm where σ is the standard deviation. FEA operation at about 10V is demonstrated.