Effects of phosphorus doping on the bending strength of a single crystal silicon microbeam

The effects of phosphorus doping on the bending strength of a single crystal silicon (SCS) microbeam are reported. First, a specially designed bending microstructure test and a simple bending test device are presented. Secondly, the results of bending strength tests for six groups of specimens with different phosphorus doping concentrations are presented. The test results are comparatively analysed using a Weibull distribution, revealing that the bending strength has a monotonically increasing relationship with the phosphorus concentration. The effect of surface roughness on the bending strength is also investigated. Finally, the mechanism underlying this phenomenon is demonstrated. The results indicate that the bond strength of a phosphorus-silicon pair is larger than that of a silicon-silicon pair, and the phosphorus atoms increase the energy necessary to create new surfaces. Therefore more energy is required to fracture the microbeam, and the fracture strength increases. Research on this topic therefore shows some practical significance for improving the bending strength of a SCS microstructure.