Adhesive Contact Modeling of Ultra-Low Flying Head-Disk Interfaces With and Without Roughness Effects

The head-disk interface (HDI) designed for sub-5nm pseudo-flying to obtain extremely high areal recording (EHDR) density of 1 Tbit/in is susceptible to strong adhesive interfacial forces, and the accurate predictions of these interfacial forces are critical in ensuring successful implementation of ultra-low flying HDI’s. In this paper, the effect of surface roughness on the adhesive forces at sub-5 nm flying-height regimes is investigated through a comparison to a simple two flat parallel surface counterpart. It was found that the effect of roughness promotes adhesion at higher separations than if a two flat parallel surface configuration is adopted. Prior to the onset of contact (during flying), however, the total adhesive force for an interface with low roughness is comparable to the two flat parallel surface approximation, thus significantly simplifying the analysis.