Patent ID: 7157054

Claim:
A gas sensor comprising: a semiconductor substrate, which has an opening; and a sensing membrane, which is located at an end of the opening to make up a recess in combination with the opening and includes: a gas sensitive film; a heater made of polycrystalline silicon; a pair of gas-sensitive-film extension electrodes made of polycrystalline silicon, wherein a first end of each gas-sensitive-film extension electrode is in electric contact with the gas sensitive film and a second end of each gas-sensitive-film extension electrode extends outward from the sensing membrane; and a pair of heater extension electrodes made of polycrystalline silicon, wherein a first end of each heater extension electrode is in electric contact with the heater and a second end of each heater extension electrode extends outward from the sensing membrane, wherein the gas-sensitive-film extension electrodes and the heater are provided on a same layer of the semiconductor substrate.