Identification and Detection of Semiconductor Varistor-type Intake Air Pressure Sensor 1

(1) Identification of Semiconductor Varistor-Type Intake Air Pressure Sensordiode

The semiconductor piezoresistive pressure sensor is fabricated using the piezoresistive effect of semiconductors. It features small size, high precision, excellent responsiveness, good reproducibility, and strong shock resistance, along with low production costs, making it widely applicable. For instance, automotive manufacturers such as General Motors, Toyota, and Chrysler, as well as domestically produced Santana 2000 GLi sedans, utilize semiconductor piezoresistive pressure sensors.

The structure of this sensor is shown in Figure 1, consisting of a pressure conversion element and a hybrid integrated circuit that amplifies the output signal of the conversion element.diode

Figure 1: Vacuum-type intake manifold pressure sensor

The pressure transducer element is a silicon diaphragm fabricated using the voltage effect of semiconductors. One side of the silicon diaphragm is a vacuum chamber, while the other side is exposed to the intake manifold pressure. The diaphragm is a square with a side length of 3 mm, and its center is formed into a thin film with a diameter of approximately 2 mm and a thickness of about 5 μm through photolithographic etching. The film is surrounded by four strain resistors connected in a Wheatstone bridge configuration, as shown in Figure 2.diode