A novel bottom-up fabrication process for controllable sub-100 nm magnetic multilayer devices

We present a fabrication process for controllable sub-100 nm magnetic multilayer devices, pseudo spin valve, using a novel bottom-up technique. Stack of multilayer devices with diameter in nanometer scales were successfully made through a template of Ge/Si0₂ stencil mask with very well undercutting profile of Si0₂ insulating layer. The niche of using this method is that a device with diameter below 100 nm can be made through a twice larger Ge hole of stencil mask. The desired dimension of the active device layers was achieved with a thick buffer metal layer deposited first, giving rise to a narrower neck for later active layers deposition. Moreover, this stencil mask technique can be utilized as device templates of not only magnetic multilayer devices but also other nano-sized devices such as phase changed memory devices.