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随着器件尺寸进一步等比例缩小,高k材料HfO2作为俘获层的电荷俘获型存储器展现了较好的耐受性和较强的存储能力,且工艺相对简单,与传统半导体工艺完全兼容,因此得到了广泛的研究.为研究HfO2中氧空位引入的缺陷能级对电荷俘获型存储器存储特性的影响,运用第一性原理计算分析了HfO2中的氧空位缺陷.通过改变缺陷超胞中的电子数模拟器件的写入和擦除操作,发现氧空位对电荷的俘获基本上不受氧空位之间距离的影响,而氧空位个数则影响对电子的俘获,氧空位数多,俘获电子的能力就强.此外,四价配位的氧空位俘获电子的能力比三价配位的氧空位大.态密度分析发现四价配位的氧空位引入深能级量子态数大,并且受氧空位之间的距离影响小,对电子的俘获概率大.结果表明,HfO2中四价配位的氧空位缺陷有利于改善电荷俘获型存储器的存储特性.
As the device size is further reduced in scale, HfO2, a high-k material, as a trapped charge-trapping memory device shows good resistance and strong storage capacity with a relatively simple process and is fully compatible with conventional semiconductor processes, resulting in In order to study the influence of oxygen vacancies introduced in HfO2 on the storage characteristics of charge-trapping memory, oxygen vacancy defects in HfO2 were calculated by first-principles calculations. By changing the number of defects Simulation of device writing and erasing operations and found that oxygen vacancies charge trapping is basically not affected by the distance between oxygen vacancies, and the number of oxygen vacancies affect the electron capture, oxygen vacancies, the ability to capture electrons It is strong.In addition, the tetravalent coordination oxygen vacancy capture electron than the trivalent coordination oxygen vacancies.Statistical density analysis found that the introduction of tetravalent coordination oxygen vacancies into the deep level quantum state number, and by the oxygen vacancies And the probability of electron trapping is high.The results show that the defect of oxygen vacancies in tetravalent coordination HfO2 is beneficial to improve the memory characteristics of charge trapping memory.