【作者】 赵晓锋；

【导师】 温殿忠；

【作者基本信息】 黑龙江大学 ， 微电子学与固体电子学， 2008， 博士

【摘要】 随着科学技术的飞速发展,在航空航天、环境监测、工业生产、医学、军事等领域,经常需要对压力、温度、磁场、湿度、加速度和流速等多个参数进行同时测量。在不同应用领域,针对环境适应性、体积、成本和功能的限定,对传感器的小型化、多功能化、集成化和一体化要求受到了广泛关注。本课题采用CMOS工艺和MEMS技术设计、制作以纳米硅/单晶硅异质结为源极（S）和漏极（D）的MOSFETs压/磁多功能传感器,本文主要进行以下五个方面的研究工作:1.纳米硅薄膜制备及特性研究采用LPCVD在衬底温度620℃时实现单晶纳米硅和多晶纳米硅薄膜制备,通过拉曼光谱（Raman spectroscopy）、X射线衍射（XRD）、扫描电子显微镜（SEM）和原子力显微镜（AFM）对纳米硅薄膜微结构进行表征研究。表征结果给出,在薄膜厚度为30.7nm时,晶粒大小5～8nm,取向为<111>晶向,随薄膜厚度增加,取向显著且多晶特征明显,沉积薄膜多晶取向为<111>、<220>和<311>晶向,择优取向为<111>晶向。对于同一厚度的纳米硅薄膜,随退火温度升高,X射线衍射峰强度增强。本文采用薄膜厚度为30.7nm的纳米硅薄膜制作以纳米硅/单晶硅异质结为源极和漏极的MOSFETs压/磁多功能传感器。2.MOSFETs压/磁多功能传感器基本理论分析本文在温殿忠教授提出的JFET压/磁电效应基本理论基础上,给出MOSFETs压/磁多功能传感器在外加压力P=0、外加磁场B=0;外加压力P≠0、外加磁场B=0;外加压力P=0、外加磁场B≠0;外加压力P≠0、外加磁场B≠0等四种情况下的基本理论分析。3.纳米硅/单晶硅异质结MOSFETs压/磁多功能传感器压/磁敏感结构设计采用n型<100>晶向高阻双面抛光单晶硅片,基于CMOS工艺和MEMS技术在6mm×6mm方形硅膜的不同位置上设计由四个纳米硅/单晶硅异质结p-MOSFET沟道电阻构成的惠斯通电桥结构,实现纳米硅/单晶硅异质结MOSFETs压/磁多功能传感器压敏结构,能够完成对外加压力P的测量。采用惠斯通电桥结构中一个纳米硅/单晶硅异质结p-MOSFET,在沟道两侧距源端为0.7倍沟道长度处制作两个欧姆接触电极作为霍尔输出端,构成纳米硅/单晶硅异质结p-MOSFET Hall磁传感器,能够完成对外加磁场B的测量。为提高磁传感器灵敏度特性,设计采用惠斯通电桥中两个纳米硅/单晶硅异质结p-MOSFET霍尔输出端构成串联输出方式。4.纳米硅/单晶硅异质结MOSFETs压/磁多功能传感器基本结构及制作工艺本文在兼顾纳米硅/单晶硅异质结MOSFETs压/磁多功能传感器中压力传感器特性和磁传感器特性基础上,设计给出纳米硅/单晶硅异质结MOSFETs压/磁多功能传感器基本结构。采用CMOS工艺和MEMS技术实现纳米硅/单晶硅异质结MOSFETs压/磁多功能传感器芯片的集成一体化制作与封装。5.纳米硅/单晶硅异质结MOSFETs压/磁多功能传感器特性实验结果主要从以下四个方面给出纳米硅/单晶硅异质结MOSFETs压/磁多功能传感器基本特性的实验结果:（1）当外加压力P=0、外加磁场B=0时本文采用CMOS工艺实现以纳米硅/单晶硅异质结为源极和漏极的p-MOSFET器件制作,在V_DS和V_GS恒定时,纳米硅/单晶硅异质结p-MOSFET沟道电流I_DS与沟道长宽比（L:W）成反比。（2）当外加压力P≠0、外加磁场B=0时在方形硅膜厚度和传感器工作电压V_DD恒定时,纳米硅/单晶硅异质结MOSFETs压力传感器满量程（160kPa）输出与沟道长宽比成正比。当方形硅膜厚度为75μm、工作电压V_DD=-1.5V时,长宽比为6:1的6SD MOSFETs压力传感器满量程输出21.04mV,灵敏度为0.132mV/kPa,线性度0.589%F.S,重复性0.571%F.S,迟滞0.412%F.S,精度0.82%F.S,灵敏度温度系数为-1550ppm/℃。（3）当外加压力P=0、外加磁场B≠0时本文提出采用栅极外加偏置电压V_GS调整纳米硅/单晶硅异质结p-MOSFETHall器件导电沟道等效电阻,使不等位电势V_HO接近零位输出,在相同工作条件下,与不等位电势补偿电路调零方法相比较,采用栅极外加偏置电压V_GS对不等位电势调零可提高磁灵敏度。在不等位电势调零方式和工作电压V_DS恒定时,纳米硅/单晶硅异质结p-MOSFET Hall磁传感器灵敏度与沟道宽长比（W:L）成正比。采用补偿电路对不等位电势调零后,在V_DS=-7.0V时,长宽比为2:1的纳米硅/单晶硅异质结p-MOSFET Hall磁传感器绝对磁灵敏度为21.26mV/T,线性度为0.156%F.S,重复性为1.719%F.S,迟滞为0.247%F.S,精度为1.834%F.S;长宽比为4:1的纳米硅/单晶硅异质结p-MOSFET Hall磁传感器,磁灵敏度为13.88mV/T,当采用栅极偏置电压V_GS对不等位电势调零时,磁灵敏度为16.48mV/T;当两个长宽比4:1的纳米硅/单晶硅异质结p-MOSFET Hall器件输出端构成串联输出方式,霍尔输出端串联输出磁传感器磁灵敏度为22.74mV/T,比单个纳米硅/单晶硅异质结p-MOSFET Hall磁传感器灵敏度提高约64%。（4）当外加压力P≠0、外加磁场B≠0时实验结果表明,纳米硅/单晶硅异质结MOSFETs压/磁多功能传感器输入—输出特性实验曲线随外加压力和磁场而发生变化。本文设计、制作的纳米硅/单晶硅异质结MOSFETs压/磁多功能传感器能够完成压力和磁场的检测,具有良好的压敏特性和磁敏特性,实现压/磁检测的集成化和一体化。更多还原

【Abstract】 With the development of technology,we usually need to measure parameters of pressure,temperature,magnetic field,humidity,acceleration,velocity of liquid,etc.at the same time,and these parameters are used in the fields of spaceflight,industry production,medicine,military affairs and so on.In many different application fields, due to the limits to adapting to environment,volume,cost and function,we need to pay much attention to miniaturization,multifunction,integration and all-in-one widely.The paper adopted CMOS technology and MEMS technology to design and fabricate MOSFETS pressure-magnetic multi-sensor taken nc-Si/c-Si heterojunetion as source and drain,and mainly researched the following five aspects:1.Fabrication and characteristics research on ne-Si thin filmsWe fabricated single crystalline and polyerystalline nc-Si thin films by LPCVD at 620℃,and then adopted Raman,XRD,SEM and AFM,etc.to do token research about micro-structure of the nc-Si thin films.The token result showed:when thickness of the thin films was 30.7nm,sizes of crystalline grains were 5～8nm,and orientation was <111>,orientation and polycrystalline characteristics were obvious with increasing thickness of the thin films,polycrystalline orientations of the deposited thin films were <111>,<220>and <311>,good orientation was <111>.Intensity of X-ray diffraction crests increased with annealing temperature for nc-Si thin films with the same thickness. The paper adopted nc-Si thin films with film thickness 30.7nm to fabricate MOSFETs pressure-magnetic multi-sensor,which took nc-Si/c-Si heterojunction as source and drain.2.Basic theory analysis of the MOSFETs pressure-magnetic multi-sensorThe paper presented basic theory analysis about the MOSFETs pressure-magnetic multi-sensor,which was based on the basic theory of JFET pressure-magnetic multi-sensor presented by Dianzhong Wen professor,the basic theory analysis of the MOSFETS pressure-magnetic multi-sensor concluded four conditions:When additional pressure P=0,additional magnetic field strength B=0;When the additional pressure P≠0, the additional magnetic field strength B=0;When the additional pressure P=0,the additional magnetic field strength B≠0;When the additional pressure P≠0,the additional magnetic field strength B≠0,etc.3.Design of pressure-magnetic sensitivity structure on the nc-Si/c-Si heterojunction MOSFETs pressure-magnetic multi-sensorAfter polishing double sides of n-type <100> p-Si wafer with high resistivity,we designed Wheatstone bridge constituted by four nc-Si/c-Si heterojunction p-MOSFET channel resistors on different positions of squared silicon membrane（6mm×6mm） by CMOS technology and MEMS technique,in order to achieve pressure-sensitivity structure of the nc-Si/c-Si heterojunction MOSFETs pressure-magnetic multi-sensor, and be able to complete the measurement to the additional pressure P.Two ohm-contact Electrodes,which were taken as Hall output on double sides of the channel situated 0.7L from the source,were fabricated by adopting nc-Si/c-Si heterojunction p-MOSFET of the Wheatstone bridge,so that nc-Si/c-Si heterojunction p-MOSFET Hall magnetic sensor could be constituted and the measurement for the additional magnetic field strength B could be achieved.In order to improve sensitivity characteristics of the magnetic sensor,we adopted two nc-Si/c-Si heterojunctions p-MOSFET Hall fan-out in series in Wheatstone bridge.4.Basic structure and fabrication technology of the nc-Si/c-Si heterojunction MOSFETs pressure-magnetic multi-sensorThe paper considered characteristics of pressure and magnetic sensors of the nc-Si/c-Si heterojunction MOSFETs pressure-magnetic multi-sensor at the same time, based on that to design and present basic structure of the nc-Si/c-Si heterojunction MOSFETs pressure-magnetic multi-sensor.Adopting CMOS technology and MEMS technique achieved fabrication of integration all-in-one and packaging for chip of the pressure-magnetic multi-sensor.5.Characteristics experimental result of the nc-Si/c-Si heterojunction MOSFETs pressure-magnetic multi-sensorThe paper mainly showed basic characteristics experimental result about the nc-Si/c-Si heterojunction MOSFETs pressure-magnetic multi-sensor from the following four respects:（1） When the additional pressure P=0,the additional magnetic field strength B=0:The paper adopted CMOS technology to achieve fabrication of the p-MOSFET device taken nc-Si/c-Si heterojunction as source and drain,when VDS and V_GS were constant,channel current I_DS of the nc-Si/c-Si heterojunction p-MOSFET was inversely proportional to length-width（L:W） ratio.（2） When the additional pressure P≠0,the additional magnetic field strength B=0:When thickness of squared silicon film and operating voltage V_DD were constant for the sensor,full range（160kPa） outputs of the nc-Si/c-Si heterojunction MOSFETs pressure sensor were directly proportional to length-width ratio of the channel.When thickness of squared silicon membrane was 75μm and operating voltage V_DD was -1.5V, full range output of 6SD MOSFETs pressure sensor with L:W ratio 6:1 was 21.04mV, and sensitivity was 0.132mV/kPa,linearity was 0.589%F.S,hysteresis was 0.412%F.S, precision was 0.82%F.S,temperature coefficient of sensitivity was-1550ppm/℃.（3） When the additional pressure P=0,the additional magnetic field strength B≠0:The paper adopted additional biased voltage V_GS of gate to adjust conducting channel equivalent resistors of the nc-Si/c-Si heterojunction p-MOSFET Hall device,so that different potentials V_OH were close to zero outputs,in the same operating circumstance,adopting additional biased voltage V_GS to adjust zero to different potentials could improve sensitivity compared with adjusting zero of compensation circuit to different potentials.When different potentials was adjusted zero and operating voltage V_DS was constant,sensitivity of the nc-Si/c-Si heterojunction p-MOSFET Hall magnetic sensor was directly proportional to channel W:L ratio,after adopting compensation circuit to adjust zero to different potentials,when V_DS=-7.0V,absolute sensitivity of the nc-Si/c-Si heterojunction p-MOSFET Hall magnetic sensor with L:W ratio 2:1 was 21.26mV/T,linearity was 0.156%F.S,repeatability was 1.719%F.S, hysteresis was 0.247%F.S,precision was 1.834%F.S;magnetic sensitivity for the nc-Si/c-Si heterojunction p-MOSFET Hall magnetic sensor with L:W ratio 4:1 was 13.88mV/T,when different potentials were adjusted zero by additional biased voltage V_GS of the gate,magnetic sensitivity was 16.48mV/T;When two fan-out of nc-Si/c-Si heterojunction p-MOSFET Hall device with L:W ratio 4:1 were in series,magnetic sensitivity of Hall fan-out of the magnetic sensor was 22.74mV/T,which was improved by about 64%compared with sensitivity of single nc-Si/c-Si heterojunction p-MOSFET Hall magnetic sensor.（4） When the additional pressure P≠0,the additional magnetic field strength B≠0:Experimental result showed that input-output experimental characteristics curves of the nc-Si/c-Si heterojunction p-MOSFET Hall pressure-magnetic multi-sensor would change with additional pressure and magnetic field.The nc-Si/c-Si heterojunction MOSFETs pressure-magnetic multi-sensor designed and fabricated in the paper,can achieve the measurements for pressure and magnetic field,and owns super characteristics of pressure sensitivity and magnetic sensitivity,and also achieve the integration and all-in-one for measurement of pressure-magnetic.更多还原