【作者】 李泽宏；

【导师】 李肇基；

【作者基本信息】 电子科技大学 ， 微电子学与固体电子学， 2004， 博士

【摘要】 非均匀沟道DMOS(Diffused Metal-Oxide-Semiconductor)基本特性的研究是新一代高压功率MOS器件和集成电路的重要新领域——智能功率集成电路研究的基础。本文对非均匀沟道DMOS的基本参数及其辐照理论进行了深入研究。在国际上首次提出微米级和深亚微米级非均匀沟道DMOS阈值电压模型和辐照阈值电压、迁移率模型及单粒子辐照瞬态响应模型。理论研究和模型的提出为下一代功率器件和电路的研究奠定良好的基础。主要研究成果如下:提出非均匀沟道DMOS二维阈值电压模型。它包含微米和深亚微米级DMOS阈值电压模型。基于非均匀沟道杂质的二维分布,求解Poisson方程获得沟道耗尽层宽度的变化,计算沟道中二维耗尽层电荷总量,给出微米级DMOS阈值电压解析式。计及沟道区杂质的二维非均匀分布、平衡态能级对沟道各点表面势的影响和栅电容的边缘效应,给出深亚微米DMOS的阈值电压二维解析式。借助二维仿真器MEDICI给出微米和深亚微米DMOS阈值电压的数值解,结果表明,解析值与实验结果和数值解吻合。还给出了沟道表面扩散浓度在2.0×1016cm-3到10.0×1016cm-3范围内微米级DMOS器件的阈值电压的简明计算式。提出非均匀沟道DMOS辐照迁移率和阈值电压模型。提出与“Hydrogen Ion Transport”相关的界面态产生模型。该界面态产生模型能较好的阐述现今电离辐照下界面态产生的过程。基于沟道杂质的非均匀分布,借助镜像法导出非均匀沟道辐照正空间电荷和沟道中电离杂质的二维场及其作用,给出非均匀沟道DMOS器件辐照正空间电荷与沟道杂质的二维互作用势。同时求解Poisson方程,分别给出非均匀N沟和P沟DMOS的辐照迁移率表示式和辐照正空间电荷阈值电压表示式。非均匀沟道DMOS辐照正空间电荷迁移率模型和辐照正空间电荷阈值电压模型的解析值与二维仿真器MEDICI数值值吻合。DMOS和常规MOS的辐照迁移率、辐照阈值电压的解析值与文献实验数据一致。提出非均匀沟道DMOS单粒子辐照的瞬态响应模型。基于单粒子辐照的等离子体输运机理,借助对横向高压DMOS的关态和开态的不同能量粒子辐照瞬态响应的二维数值分析,获得在双结、单结和无结情况下的瞬态响应特性。结果表明,横向高压DMOS的开态漏端峰值电流比关态的漏端峰值电流小,且漏端峰值电流和峰值电流出现的时间随入射粒子能量的增大而增加。同时,提出单粒子辐照临界能量的概念,给出临界能量的经验解析式。基于上述模型,实验研究了SOI(Silicon on Insulator)非均匀沟道DMOS器<WP=6>件的功率转换特性。DMOS器件瞬态特性的上电响应为:首先,衬底电流随时间增加而增大直至衬底刚形成耗尽电容;其次,衬底耗尽过程:随耗尽层的展宽变小,总串联电容放电,变小,由耗尽电容与表面势的函数关系,这一过程非常短暂;衬底反型后,耗尽层不变,逐渐增大直至漏端电压不再变化为止。在功率转换电路方面,简单介绍了以SOI为基的器件电路模型参数提取、版图设计、投片工艺以及实验结果。更多还原

【Abstract】 Researching the non-uniform channel DMOS is the basic knowledge of the new generation high voltage power MOS devices and the important domain of the IC —— smart power ICs. This dissertation investigates the basic parameters and the radiation theory of non-uniform channel DMOS. The threshold voltage model of micron and deep sub-micron non-uniform channel DMOS, the radiation threshold voltage model, the radiation mobility model and the transient response model of single ion radiation are internationally proposed for the first time. Theory study and model constitution would establish foundation of the next generation power devices and power circuits. The author’s main contributions are outlined as following: The 2-D threshold voltage models of non-uniform channel DMOS is proposed. The model includes the micron and deep sub-micron non-uniform channel DMOS. Based on the 2-D distribution of channel impurity, Resolved the Poisson equation, the channel depletion width is obtained. So the channel depletion charge is calculated and the mathematics expression of the micron level threshold voltage model is obtained. The non-uniform channel impurity, the non-equal surface potential for the changing of balance energy band and the gate capacitor by the edge effect is thought about; the mathematics expression of the deep sub-micron non-uniform channel DMOS threshold voltage model is obtained. The results of the threshold voltage model agree well with those of the experiment, and those of the 2-D simulator MEDICI. The simplified expression of DMOS threshold voltage is given with the channel surface diffusion concentration changing from 2.0×1016cm-3 to 10.0×1016cm-3. The radiation mobility shift model and threshold voltage model of the non-uniform channel DMOS are proposed. The interface state model related with the “Hydrogen Ion Transport” is proposed. The producing process of the interface state at the total ion dose is primely analyzed using the interface state model. Based on the 2-D distribution of channel impurity, the distribution of 2-D electric field and 2-D interaction potential, which is caused by the interaction between the ionized impurity in the depletion layer and radiation induced positive spatial charge, is analyzed by using image charge method. Resolving Poisson equation, the mobility expression of N-type and P-type non-uniform channel MOS and the mathematics expression of the threshold voltage model of DMOS are obtained. The results of the models agree well with those of the 2-D simulator MEDICI. Uniform channel MOS’s mobility and threshold voltage shift values agree with that of the experiment in the files. <WP=8>The transient response model of single ion radiate the non-uniform channel DMOS is proposed. Based on the transport mechanism of the single ion radiate plasma, the transient response characters of DMOS at non-junction, single junction and double junction are obtained by the transient response numerical analysis result of the open and close state of the DMOS at different energy ion radiation. Indicated that the peak value drain current of the on state is bigger than that of the off state, the peak value drain current and the arisen time of the peak value drain current are increased while the energy of the ion is increased. The critical energy of the single ion radiation is taken out. The mathematics expression of the critical energy is obtained. Based on these models, the power conversion characters of non-uniform channel DMOS is researched in experiments. The process of DMOS’s electrify transient character is divided to three parts. First, the insulator layer capacitor is charged. Accumulated state of the sub-layer is changed to depleted state, the depletion capacitor is not formed and the current of the sub-layer is increasing until the depletion capacitor is forming, when the depletion capacitor affects the total capacitor, is increased to the peak value. Second, the parasitical capacitor is becoming small while the total capacitor is discharged for the depletion width is increasing,更多还原