High-temperature co-fired ceramics（ HTCC） technology is used to design and fabricate the sensitive core of the semiconductor gas sensor.The sensitive core has a two-layer structure

that is

the heating layer and the interdigital electrode layer.Magnetron sputtering technology is ueed to fabricate SnO

2

thin film sensitive layer on the interdigital electrode layer to make the gas sensor.Gas sensing performance test is carried out.Results of the gas sensor show that the sensor has excellent gas sensitivity to NO

2

gas at a working temperature of 300 ℃

which can achieve quick response in the volume fraction range of（ 10～ 200） × 10-6 of NO

2

gas

the sensitivity is as high as 32.3 at 100 × 10-6 vo

lume fraction

and the response/recovery time is 2.2/2.6 s.The consistency of sensors is good.