深亚微米GGNMOS器件ESD鲁棒性的优化与模拟

基于单指条栅接地N型场效应晶体管(GGNMOS)在静电放电(ESD)时的物理级建模方法,仿真分析了版图参数和工艺参数对器件ESD鲁棒性的影响。提出了一种可提高器件ESD保护性能的优化设计,即硅化扩散工艺下带有N阱的多指条GGNMOS结构。对单指条器件模型进行修正,得到的多指条模型能预估不同工艺条件下所需的N阱长度,以满足开启电压V_t1小于热击穿电压V_t2的设计规则。由仿真结果可知,对于一个0.35 μm工艺下的10指条GGNMOS,通过减小栅极长度(L)、提高衬底掺杂浓度(NBC)和漏极掺杂浓度(NE),以及从修正模型中得到合适的N阱长度,均可以增强器件的ESD鲁棒性。     

PMOS管工艺参数对反相器SET效应的影响

研究了体硅CMOS工艺下数字集成电路的抗辐照特性。利用Synopsys公司的三维半导体器件模拟软件Sentaurus,对数字集成电路中的反相器电路进行单粒子瞬态(SET)效应仿真,分析PMOS管的各种工艺参数对反相器SET效应产生的脉冲电压的影响。研究结果表明,通过降低PMOS管的栅氧层厚度、n阱掺杂浓度、p+深阱掺杂浓度以及提高衬底浓度,可以有效地减小反相器SET脉冲电压的峰值和脉冲宽度。该研究结果对抗辐照数字集成电路设计具有一定的指导作用。     

一种低电压低功耗高PSRR CMOS基准电路

设计了一种工作在亚阈值区的高精度、低电压、低功耗CMOS基准电路。电路采用0.18 μm CMOS工艺实现,在1.2 V电源电压下,输出202 mV的基准电压,在-40 ℃~130 ℃范围内的温度系数为6.5×10-5/℃,消耗2.46 μA电流。电源电压从1.1 V变化到3.6 V时,输出基准电压仅变化0.336 mV。该基准电路的电源电压抑制比(PSRR)在直流处达到-93 dB,10 MHz处达到-63 dB。设计了一种多路快速启动电路,只需13 μs即可完成启动。利用高阈值电压晶体管与普通阈值电压晶体管的V_th之差作为负温度系数电压源,使输出基准电压对工艺角不敏感。     

基于层次分析法的软件质量评价方法的研究与应用

质量评价是质量改进的基础,软件质量评价旨在改进软件质量。本文探索基于层次分析法来客观评价软件质量,软件质量模型采用基于ISO/IEC 25010：2011的软件质量模型,实现软件质量评价分三个步骤执行,首先,分多层次细化软件质量评价指标;然后,用层次分析法确定评价指标的相对权重;最后,进行软件质量评价,并转换为百分制的评价分值。     

过程质谱仪测量气体浓度快速变化过程的应用研究

通过实验研究了微型流化床多阶段原位反应分析仪( MFB-MIRA)检测快速气固反应气体逸出过程的适应性。研究表明,取样毛细管的伴热性能对在线测量的稳定性有重要影响。基于所得规律,将精密温控器配置于毛细管的伴热系统,毛细管温度的控制精度达到±0.2℃,从而实现了取样流量和腔室真空度的稳定化。实测结果表明,改造后在线测量的周期性波动消失,稳定性显著提高。空气中O2测量响应的波动度和30 s相对标准偏差由1.9％和0.5％,优化至1.4％和0.2％。同时还开发了精确控制取样点绝对压力的调节装置,使取样点绝对压力的控制精度达到±0.02 kPa。实验结果表明,取样点绝对压力与过程质谱仪的响应呈正相关,准确控制取样点绝对压力非常必要。本研究提高了过程质谱仪测量结果的准确性和重复性,提升了MFB-MIRA分析快速气固反应的适应性,进而拓宽了MFB-MIRA及过程质谱仪可靠应用的范围。     

Confidence limits for contribution plots in multivariate statistical process control using bootstrap estimates

In Multivariate Statistical Process Control, when a fault is expected or detected in the process, contribution plots are essential for operators and optimization engineers in identifying those process variables that were affected by or might be the cause of the fault. The traditional way of interpreting a contribution plot is to examine the largest contributing process variables as the most probable faulty ones. This might result in false readings purely due to the differences in natural variation, measurement uncertainties, etc. It is more reasonable to compare variable contributions for new process runs with historical results achieved under Normal Operating Conditions, where confidence limits for contribution plots estimated from training data are used to judge new production runs. Asymptotic methods cannot provide confidence limits for contribution plots, leaving re-sampling methods as the only option. We suggest bootstrap re-sampling to build confidence limits for all contribution plots in online PCA-based MSPC. The new strategy to estimate CLs is compared to the previously reported CLs for contribution plots. An industrial batch process dataset was used to illustrate the concepts.     

Synthesis of representative critical path circuits considering BEOL variations for deep sub-micron circuits

The proportion of interconnect delay in the critical path on a chip is increasing and becomes over 20% in sub-10nm technologies, which means in order to capture post-Si performance accurately, the representative critical path circuit should reflect not only FEOL (front-end-of-line) but also BEOL (back-end-of-line) variations. Since the number of BEOL metal layers exceeds ten and the layers have variation on resistance and capacitance intermixed with resistance variation on vias between them, a very high dimensional design space exploration is necessary to synthesize a representative critical path circuit which is able to provide an accurate performance prediction. To this end, we propose a BEOL-aware methodology of synthesizing a representative critical path circuit, which is able to incrementally explore, starting from an initial path circuit on the post-Si target circuit, routing patterns (i.e., BEOL reconfiguring) as well as gate resizing on the path circuit. Precisely, our synthesis framework of critical path circuit integrates a set of novel techniques: (1) extracting and classifying BEOL configurations for lightening design space complexity, (2) formulating BEOL random variables for fast and accurate timing analysis, and (3) exploring alternative (ring oscillator) circuit structures for extending the applicability of our work. In summary, our synthesis framework is able to reduce the prediction error by 54% and 19% on average over that using the conventional critical path replica and using the conventional method exploiting gate sizing only, respectively.     

On-line monitoring of biotechnological processes by gas chromatographic-mass spectrometric analysis of fermentation suspensions

An on-line monitoring system has been developed for the control of a biorreactor for the anaerobic pretreatment of an industrial waste water. The monitoring system is based on a process mass spectrometer with a temperature controlled membrane inlet. The membrane introduction mass spectrometer (MIMS) is coupled with a resistively heated metal gas chromatography capillary column, which serves as a transfer line between the bioreactor and the MIMS. Sampling and injection is performed by means of a pneumatically driven membrane probe, which enables monitoring of soluted and gaseous substances in the fermentation broth. The system can also be coupled to other processes.     

高浓度试液流动注射在线稀释方法的研究

将分散－区域采样法用于高浓度试液的流动注射在线稀释，并考察了分散管的长度、管径、两次进样的时间间隔等因素对分散度的影响。方法的精密度优于区域采样法，相对标准偏差小于３％。