Figure 4

AFM images of silicon exposed to 500 eV argon ions at 72.5° incidence angle. At fluences of (a) 1 × 10¹⁷, (b) 2 × 10¹⁷, (c) 5 × 10¹⁷, (d) 10 × 10¹⁷, (e) 15 × 10¹⁷, and (f) 20 × 10¹⁷ ions cm^-2, respectively. The corresponding height scales for (a to f) are the following: 4, 3.6, 73.9, 85.9, 165.2, and 154.1 nm. For clarity, (a, b) have a scan size of 1 × 1 μm², whereas (c to f) have a scan size of 2 × 2 μm². Insets show the 2D autocorrelation functions for corresponding images.