Scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM) both are capable of
mapping the 2-demensional carrier distribution in semiconductor device structures, which is essential in determining their electrical and optoelectronic performances. In this work, cross-sectional SCM<sup>1,2</sup> is used to study the InGaAs/InP P-i-N junctions prepared by area-selective p-type diffusion. The diffusion lengths in the depth as well as the lateral
directions are obtained for junctions under different window sizes in mask, which imply that narrow windows may result in shallow p-n junctions. The analysis is beneficial to design and fabricate focal plane array of near infrared photodetectors with high duty-cycle and quantum efficiency. On the other hand, SSRM provides unparalleled spatial resolution (<10 nm) in electrical characterization<sup>3</sup> that is demanded for studying low-dimensional structures. However, to derive the carrier density from the measured local conductance in individual quantum structures, reliable model for SSRM is necessary but still not well established. Based on the carrier concentration related transport mechanisms, i.e.
thermionic emission and thermionic field emission<sup>4,5</sup>, we developed a numerical model for the tip-sample Schottky
contact<sup>4</sup>. The calculation is confronted with SSRM study on the dose-calibrated quantum wells (QWs).
Manganese cobalt nickelate films (Mn<sub>x</sub>Co<sub>y</sub>Ni<sub>3-x-y</sub>)O<sub>4</sub> (MCN) are successfully prepared by chemical deposition method
at a crystallization temperature of 600°C, which is greatly reduced from the traditional sintered temperature of ~1050 -
1200°C. From the XRD and AFM, we find the grain size of the MCN films increases from 20 to 60 nm with the
annealing temperature increase from 600°C to 900°C.
AlGaN is am important ultraviolet optoelectronic material and inductively coupled plasma (ICP) etching plays an
important role in fabrication of mesa structures of AlGaN-based photodiodes. In this work, we investigate ICP etching
processes of Al<sub>0.32</sub>Ga<sub>0.68</sub>N and Al<sub>0.47</sub>Ga<sub>0.53</sub>N. The Al<sub>0.32</sub>Ga<sub>0.68</sub>N and Al<sub>0.47</sub>Ga<sub>0.53</sub>N materials were firstly tested by
transmission spectra and it indicates that they are different materials with different epitaxial quality. Cl<sub>2</sub>/Ar/BCl<sub>3</sub> were
used as the ICP gases, and Cl<sub>2</sub>/Ar mixing ratio was fixed at 4:1. Etching behaviors were characterized by varying the ICP
power, the dc bias, Cl<sub>2</sub>/Ar/BCl<sub>3</sub> mixing ratio. ICP power influences etching rates. Dc bias heavily influences the etching
rates, and the etching rates increase monotonously with dc bias, which suggests that the ion-bombardment effect is an
important factor of these etching processes. BCl<sub>3</sub> is the effective removal of oxygen during the etching, and also
influences etching rates. The surface rms roughness was measured by an at omic force microscope. The ICP etching
surface morphologies were studied by Scanning Electron Microscope (SEM). The results show dc bias and BCl<sub>3</sub> are
important to electrical characteristics of epitaxial materials. At a relative high dc bias and more BCl<sub>3</sub>, the etching rate is
low, but the damage is low. These results have direct application to the fabrication of AlGaN-based ultraviolet