Radiation emits by Ir-192
Irradiation damage in In/sub 0.53/Ga/sub 0.47/As p-i-n photodiodes by 1-MeV fast neutrons is studied as a function of fluence for the first time. 
The degradation of the electrical and optical performance of diodes increases with increasing fluence. 
The induced lattice defects in the In/sub 0.53/Ga/sub 0.47/As epitaxial layers and the InP substrate are studied by DLTS methods.
In the In/sub 0.53/Ga/sub-0.47/As epitaxial layers, hole and electron capture levels are induced by irradiation. 
The influence of radiation source on device degradation is then discussed by comparison to 1-MeV electrons with respect to the numbers of knock-on atoms and the nonionizing energy loss (NIEL). In order to examine the recovery behavior, isochronal thermal annealing is carried out for temperatures ranging from 75 to 300/spl deg/C.
After 300/spl deg/C thermal annealing, the light current only recovers to 20% of pre-irradiation for a fluence of 1/spl times/10/sup 13/ n/cm/sup 2/, while it recovers to 53% for a fluence of 1/spl times/10/sup 15/ e/cm/sup 2/.
The different recovery behavior is thought to be due to a different type of radiation damage.
0.5 Mev
0.6 Mev
0.66 Mev
0.47 Mev