一种新结构微型硅电容式麦克风的研制

Fabrication of a Novel Structural Miniature Silicon Condenser Microphone

本文提出一种新型的微型硅电容式麦克风结构及制造方法；单硅片纹膜结构及制造方法，首次实现了纹膜麦克风的制作．对这种结构的麦克风进行了初步设计并制造出一系列结构尺寸的微麦克风．实现了麦克风电容两极板有效区域的自对准．实验证明，纹膜结构大大降低了膜的内应力，且使电容有所增加，因而器件的灵敏度和重复性有了极大的改善．这种微麦克风制造工艺非常简单、可靠，由于是单硅片制造，无需双／多芯片的对准、粘接或键合，大大提高了生产效率和器件的性能．另外，采用了复合膜技术，进一步提高了麦克风的灵敏度．在ｌｍｍ２的膜片上，得到了６．８～１６．０ｍＶ／Ｐａ的开路灵敏度，频率带宽在８～１６ｋＨｚ范围．

A novel type of silicon condenser microphone with corrugated diaphragm has been proposed,designed,fabricated and tested.The e microphonecan be fabficated on a single wafer by use of silicon anisotropic etching and sacrificial layer etching techniques. The introduction of well performed corrugation has strongly increased the mechanicamesensitivity of the microphone diaphragm because of the reduction of the stthss in esin fnlms.Corrugations with different q values have been investigated,showing a close relationship between the ratio of the depth of the corrugation to the diaphragm thickness and mechanical sensitivity of the diaphragm. For the purpose of further decreasing thin film stress,composite siaphragm had been fabricated,reducing the initial stress to a much lower level of about 70MPa in tension. TTree etypes of corrugation placements in a diaphragm area of lmm by lmm have been fabricated. Microphones with higher than 10kHz bandwidth and sensitivity of 6. 8～16. 0mV/Pa under a relatively low bias voltage of about 5～15V have been fabricated. The experiments prove that the corrugation technique is promising for silicon condenser microphone.