Abstract
A six-beam accelerometer with self-compensated off-axis sensitivity was fabricated onthe selectively diffused (111)-oriented n/n$^{+}$/n silicon substrates by a unique porous silicon micromachining technique, which has self-stip characteristics and highly seletive formation of porous silicon layer during anodic reaction. Also, the characteristics of the fabricated accelerometer were investigated. The sensitivity of the acceleormeter added up outputs of three bridges through a summing circuit was 0.68 mV/g and the nonlinearity was less than 2% of the full scale output. The measured first resonant frequency was 4.236 kHz. When the outputs of three bridges were compared to summing output of bridges obtained through summing circuit, the normal output for Z-axis acceleration exhibited the same value s summing outputs of three bridges without reduction of sensitivity and thus the sensitivity decrease due to additional beam was compensated. Although a maximum off-axis sensitivity in one bridge of the accelerometer showed 17% of normal sensitivity, the off axis sensitivity obtained from summing output of three bridges decreased to 1.0%. Therefore, the self-elimination of off-axis sensitivity can be simply realized by obtaining the output of the sensor through summing circuit.t.
