Figure 4: Projected charge density 
maps under different bias.
maps under different bias.From: In situ electron holography study of charge distribution in high-κ charge-trapping memory
(a) 5 V, (b) 6 V, (c) 7 V, (d) 8 V, (d) 9 V. The top-left Al2O3 layer locates in the Fresnel stripes of the hologram; hence, its second differential result may deviate from the true value in some degree. The inversed layer of p-Si can be observed beneath the SiO2 film as a slight negative stripe. The dashed lines indicate the position of grain boundary, as shown in Fig. 2c,d. Scale bar, 5 nm.
