Low-frequency noise in proton damaged LDD MOSFET's

One of the concerns in the design of a guide camera for a satellite astrono my mission was an increase in the low-frequency noise in the output amplifi er of the charge-coupled device (CCD) image sensor due to the radiation env ironment of the satellite, We investigated this potential problem by measur ing the noise in several MOSFET's which had been subjected to varying amoun ts of high-energy proton radiation. These MOSFET's were typical of those us ed in the output stage of a CCD, They were lightly-doped drain (LDD) n-type buried-channel devices with aspect ratios between 4 and 6, We found a significant increase in the low-frequency noise of our devices a fter radiation, The frequency and temperature dependence of the noise indic ates that it is generation-recombination noise due to the introduction of b ulk trapping states. Fortunately, at the operating temperature of the CCD i n the guide camera (-50 degrees C), the noise increase is very small in the frequency range of interest. However, at room temperature, the noise incre ase is large.