Measurement and Evaluation of Defects induced by Processing of Small Regions by means of Interface-Barrier-Controlled Electron Spin Resonance

为了了解由半导体加工引起的硅小区域缺陷或杂质的电子能级以及几何和电子结构，我们用电极测量了界面势垒控制的电子自旋共振（ESR），并开发了一种分析温度相关ESR线宽的新方法。在本研究中，通过离子注入和随后的激光退火，在2000 A的硅表面层中引入偏离中心的取代氮来获得样品。对于界面势垒控制的ESR，通过控制氧化物-硅界面势垒形成金属-氧化物-半导体结构来检测ESR的变化。我们为这个测量澄清了几个问题；即：(1)由于电极的大面积（20 x 2mm ^2）而产生的漏电流和(2)氧化物-硅界面附近的残留缺陷。要推进这一方法，必须解决这些问题。对于新开发的方法，我们证明了通过分析在150 ~ 550 K宽温度范围内获得的ESR线宽可以确定硅中偏离中心取代氮的电子水平。在330k以上观察到的温度依赖性被解释为自旋晶格弛豫时间的运动展宽或缩短，这是通过传导带的热激发和深能级捕获来实现的。根据这一分析，我们得到了E_c - 0.33 eV的能级，并表明该方法对缺陷能级和结构的确定是非常有用的。

In order to know electronic levels as well as geometrical and electronic structures of defects or impurities in small regions of silicon which are induced by semiconductor processings, we have measured the interface-barrier-controlled electron spin resonance (ESR) by using electrode and have developed a new method of analyzing the temperature dependent ESR linewidth. In this study, the off-center substitutional nitrogen was introduced in silicon surface layer of 2000 A by ion implantation and subsequent laser annealing to obtain the samples.For the interface-barrier-controlled ESR, metal-oxide-semiconductor structure was formed to detect ESR changes by controlling the oxide-silicon interface-barrier. We clarified a few problems for this measurement; i.e., (1) leak current due to the large area (20 x 2 mm^2 ) of the electrode and (2) residual defects near the oxide-silicon interface. These must be solved to advance this mothod.For the newly developed method, we demonstrated that the electronic level of off-center substitutional nitrogen in silicon can be determined by analyzing the ESR linewidth obtained over a wide temperature region from 150 to 550 K. The temperature dependence observed above 330 K is interpreted in terms of motional broadening or shortening of the spin-lattice relaxation time via thermal excitation in the conduction band and trapping by the deep level. According to this analysis, we obtain an energy level of E_c - 0.33 eV and show that this mehtod is very useful for determination of defect levels as well as the structures.