【作者】 张成伟；

【导师】 潘银松；

【作者基本信息】 重庆大学 ， 微电子学与固体电子学， 2010， 硕士

【摘要】 神经生物传感微阵列是以探测大脑内部神经信号的生物传感器,是微电子技术与神经生物学科重要结合。论文针对1×4神经传感微阵列的微弱电压信号,对CMOS读出电路以及神经微电极的制作进行了研究,为读出电路和神经微电极的系统集成打下基础。以神经生物传感微阵列为研究对象,了解神经微电极的基本结构及植入式方式,分析其电压输出信号的特点,根据探针电极的反应特性,建立微电极的电学模型。前置放大电路在读出电路中是非常重要的一部分。设计了基于前馈补偿技术的运算放大器。采用前馈补偿技术,避免了片上集成米勒补偿电容,同时也克服传统电路设计当中增益、带宽和相位裕度相互制约的问题,满足微电极信号低压、低功耗的要求。分析电阻反馈网络和电容反馈网络各自优缺点,选用电容反馈网络作为闭环反馈结构。由于前置放大电路放大倍数不足以对信号进行放大,故设计二次放大电路。二次放大电路采用轨对轨结构运算放大器,分析电路的基本结构,得到模拟仿真结果。同时采用电容反馈网络作为闭环反馈结构。分析读出电路的各种噪声,针对神经微电极读出电路的噪声,设计一种相关双采样电路,分析其双采样的原理,并进行模拟仿真。针对传感微阵列,需要设计数据选通器来控制微电极传感阵列单元。数据选通器由移位寄存器、反相器和传输门三部分组成。移位寄存器作为数据选通的核心部件,采用准静态CMOS移位寄存器电路结构,该结构具有使用元件少、功耗低等优点。最后给出了准静态CMOS移位寄存器和数据选通器的仿真结果。设计了一种结构简单的带隙基准电路,分析带隙基准电路的原理,并给出了仿真结果。在对读出电路进行模拟仿真之后,介绍了版图设计过程中应该注意的问题。采用0.5μm标准CMOS工艺规范,给出各个单元模块版图,设计了读出电路版图,并对版图进行DRC、LVS验证。最后,采用表面牺牲层技术对神经微电极的制作工艺流程进行探讨。更多还原

【Abstract】 The neurobiology sensing microarray for the biological sensors is used to detect brain nerve signals. It is combined with microelectronics technology and neural biology. This paper targeted on the 1×4 neural sensor micro array weak voltage signal, studied the CMOS readout circuit and the fabrication of neural micro probe. It can do some prepare for integratting CMOS readout circuit and neural micro probe.This paper targeted on the neural bio-sensor micro array, introduced the basic structure of neural micro probe, and analyzed the characteristic of voltage output signal, based on the response of electrode probe, built the electrical model of micro electrode.Preamplifier circuit is an important part of readout circuit. This paper designed a preamplifier based on the feed-forward compensation technology. Because of tooking the feed-forward compensation technology, the amplifier not only avoided the influence of integrating Miller compensation capacitor on the chip, but also solved the interaction problem during gain, bandwidth and phase margin in traditional circuit design. It is satisfied the need of low voltage, low power consumption of micro electrode signal. After analyzed the advantage and disadvantage of resistance feedback network and capacitor feedback network, this paper took the capacitor feedback network as the closed loop feedback structure.Because the feed-forward amplifier is not sufficient to process the signal, this paper also designed a second stage amplify circuit. The second stage circuit took the rail to rail structure operational amplifier. After analyzing the basic structure of circuit, it got the result of simulation. The second stage took the capacitor feedback network as closed loop feedback structure.This paper analyzed various noise of readout circuit, took an Correlate Double Sample structure, analyzed the theory of double sample, and simulated the structure.For the micro sensor array, it is necessary to design data selective gate to control the unit of micro probe sensor array. The data selective gate was made of shift register, inverter and transmission gate. The shift register as the key part of data selective gate, took quasi-static CMOS shift register, which had the advantage of using less devices and low power consumption. At last, this paper exhibited the simulation results of quasi-static CMOS shift register and data selective gate.It is designed a band gap circuit with simple structure, analyzed the theory of band gap circuit, and gave the simulation result.After the simulation of the circuit, this paper introduced the problems needed to pay attention to during layout. It took 0.5μm standard CMOS procedure specification, and gave the layout of each unit, designed the layout, and had the DRC, LVS test to layout.At last, the paper discussed the fabricate process chart of neural micro probe by tooking surface sacrifice layer technology.更多还原