Solid state image sensor

Abstract

Abstract PURPOSE:To minimize a dark current and eliminate the fluctuation of spectral sensitivity characteristics and further reduce the variation of the characteristics caused by the penetration of Na ions, moisture and so forth by a method wherein a film made of material containing hydrogen ions is formed on a part of a protective insulating film except at least a part of the surface of a photodiode. CONSTITUTION:An aluminum film 7 is evaporated on a silicon dioxide film 6 and a light shielding film is formed by RIE or the like and, over the whole surface, phosphorus silicate glass is deposited and silicon nitride 9 is deposited by plasma CVD. Then the silicon nitride above an N-type region 2 which is to be a photodiode is removed and annealing in mixed gas of 90% of N2 and 10% of H2 is carried out at 450 deg.C for 15-30 minutes. At the surface near a P-N junction which is a main source of a dark current, the surface level is sufficiently reduced by hydrogen diffused from the silicon nitride 9 and, on the other hand, the silicon nitride is removed from the upper part of the photodiode which has no direct relation to the dark current but has an influence upon photoelectric conversion characteristics such as spectral sensitivity characteristics.

Inventors

• 👤 Shigenori Matsumoto
• 👤 松本　茂則
• 👤 Yoshimitsu Hiroshima
• 👤 広島　義光

Bibliographic Details