In order to examine the effect of chemical treatment on silicon emitter surfaces, photolithographically processed, mechanically grooved, and crushed silicon specimens were atom-by-atom mass analyzed before and after the soakage in hydrofluoric acid (HF) by the scanning atom probe. Silicon microtips fabricated by the photolithography were found to be most heavily contaminated before the KF treatment. After the acid soakage, the [111]-oriented silicon surface is found to be most resistive to the HF treatment while other specimens are vulnerable to contaminants, possibly due to defects and disorders on the surface layers. The Fowler-Nordheim (FN) curves were plotted for all specimens. Generally, the HF treatment lowered the work function of the specimens which field evaporate hydrogen as H+ and H-2(+).