Engineering realization of triple harmonic method on in-situ FH test

Summary form only given. As technology moves to sub 10 nm slider disk spacing, it becomes more important to characterize the dynamic slider disk interaction. The optical flying height (FH) tester has its limitations on some certain dynamic processes, such as slider-lube-disk interaction, and track seeking process. The in-situ FH test methods can be the solution to the above processes and are attracting more attention now. The harmonic ratio flyheight (HRF) method uses two harmonics of all ones data pattern to in-situ test FH, which has many advantages among reported in-situ methods. But the intensity of higher order harmonic signal of its all ones pattern is too low when compared with that of its first harmonic, especially, at high user density (PW50/bitlength), and the testing accuracy is affected. In order to improve the signal intensity of higher order harmonic, the authors proposed triple harmonic method, which uses (111100) code to in-situ measure FH. From the point of view of engineering realization, this work pays more attention to the engineering issues of triple harmonic method.