Sonetics Ultrasound Inc., Ann Arbor, MI, USA.
IEEE Trans Ultrason Ferroelectr Freq Control. 2012 Jul;59(7):1521-36. doi: 10.1109/TUFFC.2012.2352.
As ultrasound imagers become increasingly portable and lower cost, breakthroughs in transducer technology will be needed to provide high-resolution, real-time 3-D imaging while maintaining the affordability needed for portable systems. This paper presents a 32 x 32 ultrasound array prototype, manufactured using a CMUT-in-CMOS approach whereby ultrasonic transducer elements and readout circuits are integrated on a single chip using a standard integrated circuit manufacturing process in a commercial CMOS foundry. Only blanket wet-etch and sealing steps are added to complete the MEMS devices after the CMOS process. This process typically yields better than 99% working elements per array, with less than ±1.5 dB variation in receive sensitivity among the 1024 individually addressable elements. The CMUT pulseecho frequency response is typically centered at 2.1 MHz with a -6 dB fractional bandwidth of 60%, and elements are arranged on a 250 μm hexagonal grid (less than half-wavelength pitch). Multiplexers and CMOS buffers within the array are used to make on-chip routing manageable, reduce the number of physical output leads, and drive the transducer cable. The array has been interfaced to a commercial imager as well as a set of custom transmit and receive electronics, and volumetric images of nylon fishing line targets have been produced.
随着超声成像仪变得越来越便携和低成本，需要在换能器技术方面取得突破，以提供高分辨率、实时的 3D 成像，同时保持便携式系统所需的经济实惠性。本文介绍了一种 32x32 超声阵列原型，该原型采用 CMUT-in-CMOS 方法制造，其中超声换能器元件和读出电路使用商业 CMOS 代工厂中的标准集成电路制造工艺集成在单个芯片上。在 CMOS 工艺之后，只需添加全覆盖湿蚀刻和密封步骤即可完成 MEMS 器件。该工艺通常可使每个阵列的工作元件超过 99%，在 1024 个可单独寻址的元件中，接收灵敏度的变化小于±1.5dB。CMUT 脉冲回波频率响应通常以 2.1MHz 为中心，-6dB 带宽分数为 60%，元件以 250μm 六边形栅格排列（小于半波长间距）。阵列内的多路复用器和 CMOS 缓冲区用于实现芯片内路由管理，减少物理输出引线的数量，并驱动换能器电缆。该阵列已与商业成像仪以及一组定制的发射和接收电子设备接口连接，并生成了尼龙钓鱼线目标的体图像。
