公开(公告)号：US07817811B2

公开(公告)日：2010-10-19

申请号：US11341655

申请日：2006-01-30

Applicant: Shinichiro Umemura ,  Takashi Azuma ,  Tatsuya Nagata ,  Hiroshi Fukuda ,  Toshiyuki Mine ,  Syuntaro Machida

Inventor： Shinichiro Umemura ,  Takashi Azuma ,  Tatsuya Nagata ,  Hiroshi Fukuda ,  Toshiyuki Mine ,  Syuntaro Machida

IPC: H04R25/00

CPC classification number: B06B1/0292

Abstract: The present invention aims to stabilize sound-electricity conversion characteristics of a diaphragm-type sound-electricity conversion device as well as to decrease the noise level of an ultrasonic diagnostic apparatus using the sound-electricity conversion device. The sound-electricity conversion device is configured by a capacitor cell including a lower electrode formed on a silicon substrate and an upper electrode over the lower electrode, the lower and upper electrodes sandwiching a cavity. An electrode short-circuit prevention film is formed on the upper electrode on the cavity side. The electrode short-circuit prevention film is formed of a material with an electrical time constant shorter than 1 second and longer than 10 microseconds, such as silicon nitride containing a stoichiometrically excessive amount of silicon. As a result, the electrode short-circuit prevention film has small electric conductivity, and thus it is made possible to prevent the film from being charged with electric charge and to avoid the drift of the electric charge. Consequently, the sound-electricity conversion characteristics of the sound-electricity conversion device stabilize, and further the sound noise level of the ultrasonic diagnostic apparatus decreases.

Abstract translation: 本发明旨在稳定隔膜式声电转换装置的声电转换特性，并且降低使用声电转换装置的超声波诊断装置的噪声水平。 声电转换装置由包括形成在硅基板上的下电极和下电极上的上电极的电容器单元构成，下电极和上电极夹着空腔。 在空腔侧的上部电极上形成电极短路防止膜。 电极短路防止膜由电气时间常数短于1秒且长于10微秒的材料形成，例如含有化学计量过量的硅的氮化硅。 结果，电极短路防止膜具有小的导电性，因此可以防止膜被充电并避免电荷的漂移。 因此，声电转换装置的声电转换特性稳定，超声波诊断装置的声音噪声水平进一步降低。

公开(公告)号：US20060284519A1

公开(公告)日：2006-12-21

申请号：US11341655

申请日：2006-01-30

Applicant: Shinichiro Umemura ,  Takashi Azuma ,  Tatsuya Nagata ,  Hiroshi Fukuda ,  Toshiyuki Mine ,  Syuntaro Machida

Inventor： Shinichiro Umemura ,  Takashi Azuma ,  Tatsuya Nagata ,  Hiroshi Fukuda ,  Toshiyuki Mine ,  Syuntaro Machida

IPC: H01L41/00

CPC classification number: B06B1/0292

Abstract: The present invention aims to stabilize sound-electricity conversion characteristics of a diaphragm-type sound-electricity conversion device as well as to decrease the noise level of an ultrasonic diagnostic apparatus using the sound-electricity conversion device. The sound-electricity conversion device is configured by a capacitor cell including a lower electrode formed on a silicon substrate and an upper electrode over the lower electrode, the lower and upper electrodes sandwiching a cavity. An electrode short-circuit prevention film is formed on the upper electrode on the cavity side. The electrode short-circuit prevention film is formed of a material with an electrical time constant shorter than 1 second and longer than 10 microseconds, such as silicon nitride containing a stoichiometrically excessive amount of silicon. As a result, the electrode short-circuit prevention film has small electric conductivity, and thus it is made possible to prevent the film from being charged with electric charge and to avoid the drift of the electric charge. Consequently, the sound-electricity conversion characteristics of the sound-electricity conversion device stabilize, and further the sound noise level of the ultrasonic diagnostic apparatus decreases.

Abstract translation: 本发明旨在稳定隔膜式声电转换装置的声电转换特性，并且降低使用声电转换装置的超声波诊断装置的噪声水平。 声电转换装置由包括形成在硅基板上的下电极和下电极上的上电极的电容器单元构成，下电极和上电极夹着空腔。 在空腔侧的上部电极上形成电极短路防止膜。 电极短路防止膜由电气时间常数短于1秒且长于10微秒的材料形成，例如含有化学计量过量的硅的氮化硅。 结果，电极短路防止膜具有小的导电性，因此可以防止膜被充电并避免电荷的漂移。 因此，声电转换装置的声电转换特性稳定，超声波诊断装置的声音噪声水平进一步降低。