A Single-Side Fabricated Triaxis (111)-Silicon Microaccelerometer With Electromechanical Sigma-Delta Modulation
A Single-Side Fabricated Triaxis (111)-Silicon Microaccelerometer With Electromechanical Sigma-Delta Modulation
复制标题
具有机电 Sigma-Delta 调制的单面装配式三轴 (111) 硅微加速度计
DOI：
10.1109/jsen.2017.2785394
复制
发表时间：
2018-03-01
影响因子：
4.3
通讯作者：
Li, Xinxin
中科院分区：
文献类型：
--
作者：
Chen, Fang;Zhao, Yi;Li, Xinxin
提出了一种新型单面(111)硅(非SOI)电容式微加速度计，该传感器具有双量化机电Sigma-Delta调制器(EM-Sigma Delta M)接口电路。描述了采用环形电隔离结构的完全兼容的单面微加工工艺。仅用4英寸(111)硅片的正面设计和制造了一种2.6 mm x 2.6 mm尺寸的三轴加速度计。该接口电路是基于前端ASIC读出电路和后端双量化高阶EM-SDM数字电路在一片FPGA上实现的。EM-Sigma Delta M环路采用多反馈噪声整形结构，分析了环路量化的不同比特数。利用遗传算法对EM-Sigma Delta M环的参数进行了优化。在EM-Sigma Delta M闭环系统中，分别测得面内(X/Y)和离面(Z)方向的加速度灵敏度分别为170 mV/g(2785 lsb/g)、142 mV/g(2327 lsb/g)和26 mV/g(426 lsb/g)。其横向灵敏度为1%~6%，输出噪声为0.5 mg~2 mg/根赫兹，1h的偏置漂移为3~6 mg。
This paper presents a novel single-side (111)-silicon (non-SOI) fabricated triaxis capacitive microaccelerometer with a dual quantization electromechanical sigma-delta modulator (EM-Sigma Delta M) interface circuit. The fully CMOS compatible single-sided micromachining process with toroidal shaped electrical isolation structures is described. A 2.6 mm x 2.6 mm sized triaxis accelerometer was designed and fabricated using only the front side of a 4-in (111) silicon wafer. The interface circuit was based on a front-end ASIC readout circuit and a back-end dual quantization high-order EM-SDM digital circuit implemented on an FPGA. The EM-Sigma Delta M loop adopts a multifeedback noise shaping architecture, for which different numbers of bits for the loop quantization were analyzed. The parameters of the EM-Sigma Delta M loop are optimized by a genetic algorithm. Acceleration sensitivities of 170 mV/g (2785 LSB/g), 142 mV/g (2327 LSB/g), and 26 mV/g (426 LSB/g) were measured in EM-Sigma Delta M closed-loop operation for the in-plane (X/Y) and out-of-plane (Z) axes, respectively. The cross-axis sensitivity was in the order of 1%-6% and the output noise was 0.5 mg-2 mg/root Hz, with a 1-h bias drift of 3-6 mg.