Monte Carlo Simulation Of Dose Enhancement Effect Of Organic Semiconductor-metal Interface

Semiconductor device with the structure of"Metallizing-Si"would be damaged by X-rays or gamma rays, the reason is that the cross-section of photoelectric effect in high-Z (atomic number) material is much larger than in low-Z material for low-energy rays, and accordingly when themetallizing is made of high-Z materials, there will be anonequilibrium fluxion of photon-electron between the high-Z region and low-Z region because of the different consistencies of two regions. Therefore,the Dose Enhancement Effect appears in the silicon with the additionalphotoelectrons diffusing from the high-Z material via the interface,and the dose enhancement factor, called DEF for short, is a important parameter in Dose Enhancement Effect, and which is defined as follows.DEF=dose of sensitive region/equilibrium doseSince the semiconductor device is very small and easily damaged, it is difficult to measure the dose distribution and the dose enhancement of these miconductor-metal irradiating with X-rays in experiment. Therefore, the Dose Enhancement Effect of the semiconductor-metal interface from different metallizing is usually obtained by theoretical calculations.In this paper, the essential principles of Dose Enhancement Effect of various material interfaces and laws of interaction between gamma-rays and matters are detailedly introduced. Dose enhancement of simple Au-Si model iscalculated by the photon-electron coupling transport Monte-Carlo method, and the result is consistent with Garth's data which is affective to this field. So the Monte-Carlo method is feasible to calculate the Dose Enhancement Effect of Metallizing- CuPc. Then the semiconductor-metal interface models of"Metallizing- CuPc"are established, according to these models, dosedistribution and dose enhancement factor (DEF) near the interface are calculated,and dose enhancement effect of the various packaging and metallizing is discussed as well.Dose distributions and Dose Enhancement Factors of Au/ CuPc,W/CuPc,Ta/CuPcare obtained. The energy range of X-rays, where the Dose Enhancement Effect occurs,is present.