Defects etching

Defects in a SCR, which is present under reverse bias, can be tested in a similar way. Figure 10.6 c shows the same wafer as in Fig. 10.6 e after removal of the oxide and under cathodic polarization in the dark. Hydrogen bubbles caused by the dark current now decorate nickel silicide precipitates that short-circuit the SCR. Nickel precipitates are known to increase the dark current of a p-type Si electrode under reverse bias by orders of magnitude [Wa4]. If the bias is increased the copper silicide precipitates also become visible, as shown in Fig. 10.6 d. This method, like defect etching (Fig. 10.4f), is only sensitive to precipitated metals. Metals that stay in solution, like iron, do not show up in defect mapping and have to be determined by other methods, for example diffusion length mapping. 

Bnlk wave devices have different tolerances and recently Capelle, Zarka and co-workers have studied bulk waves in qnartz resonators and used stroboscopy to identify unwanted modes associated with defects. They have also performed tine section topography in stroboscopic mode to identify if the interaction between a dislocation and the acoustic wave could be described by simple linear piezoelectric theory. Using simulation of the section topographs to analyse the data, they conclnded that a non-Unear interaction was present near to the dislocation line, linear theory working satisfactorily in the region far from the defect. Etch channels appeared to have more inflnence on the acoustic wave than individnal dislocations. 

There are three major etching solution systems with respect to the uniformity of the etched surface, that is, relative etching rates on silicon surfaces of different crystallographic characters (1) isotropic etching system represented by HF-HNO3, (2) anisotropic etching system represented by alkaline solutions, and (3) defect etching system represented by HF-CrOs solutions (Fig. 7.1). 

The details of the reactions on silicon electrodes in HF-CrOs solutions are presented in Chapter 6. The information on defect etching in some specific etching solntions is presented in Section 7.8.1. 

Defect etching refers to the etching process that preferentially attacks the strained bonds of defects within a crystal. It is a simple and fast method of determining the... 

The HF—CrC>3 etching system is widely used for defect etching and delineation of junctions between silicon layers of different doping concentrations [75, 115]. The etch rate of silicon in pure H F solution is very low due to the lack of holes at OCP. Addition of Cr03 increases the etch rate due to the increase of surface hole... 

Defect etching refers to the etching process that preferentially attacks the strained... 

Cu, Au PCD pulsed MOS capacitor for active layer quality, defect etching Borisenko and Dorofeev (1983) Lamedica et al. (2002) Borisenko et al. (1984)... 

Localized Avalanche Breakdown Defect Etching and Pore Formation... 

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