H Sunaga

Impact of high energy particles on InGaP/InGaAs pseudomorphic HEMTs

Irradiation damage and its recovery behavior resulting from thermal annealing in InGaP/InGaAs pseudomorphic HEMTs, subjected to a 20 MeV alpha ray and 220 MeV carbon, are studied for the first time. The drain current and effective mobility decrease after irradiation, while the threshold voltage increases in positive direction. The degradation of device performance increases with increasing fluence. The decrease of the mobility is thought to be due to the scattering of channel electrons with the induced lattice defects and also to the decrease of the electron density in the two dimensional electron gas (2DEG) region. The influence of the radiation source on the degradation and recovery is discussed by comparison with 1 MeV electron and 1 MeV fast neutron exposures with respect to the number of knock-on atoms and the nonionizing energy loss (NIEL). Isochronal thermal annealing for temperatures ranging from 75 to 300/spl deg/C shows that the device performance degraded by the irradiation recovers completely.

Degradation and recovery of In/sub 0.53/Ga/sub 0.47/As photodiodes by 1-MeV fast neutrons

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 of recovery behavior is thought to be due a different type of radiation damage.

Impact of neutron irradiation on optical performance of InGaAsP laser diodes

Abstract Results are presented of an extended study on the degradation and recovery behavior of optical and electrical performance and on induced lattice defects of 1.3 μm InGaAsP double channel planar buried heterostructure laser diodes with an In 0.76 Ga 0.24 As 0.55 P 0.45 multi-quantum well active region, subjected to a 1 MeV fast neutron and 1 MeV electron irradiation. The degradation of the device performance increases with increasing fluence. Two hole capture traps with near midgap energy level in the In 0.76 Ga 0.24 As 0.55 P 0.45 multi-quantum well active region are observed after a 1×10 16 n/cm 2 irradiation. These deep levels are thought to be associated with a Ga vacancy. The decrease of optical power is related to the induced lattice defects, leading to a reduction of the non-radiative recombination lifetime and of the carrier mobility due to scattering. The difference in radiation damage between 1 MeV fast neutrons and 1 MeV electrons is discussed taking into account the non-ionizing energy loss (NIEL). The radiation source dependence of performance degradation is attributed to the difference of mass and the probability of nuclear collision for the formation of lattice defects. The decreased optical power recovers by thermal annealing, and the recovery increases with increasing annealing temperature. The optical power recovers by 45% for 1 MeV neutron irradiation with a fluence of 1×10 15 n/cm 2 after a 300°C annealing.

Impact of induced lattice defects on performance degradation of AlGaAs/GaAs p-HEMTs

Abstract Irradiation damage and its recovery behavior resulting from thermal annealing in AlGaAs/GaAs pseudomorphic HEMTs, subjected to 1-MeV electrons, 1-MeV fast neutrons and 220-MeV carbon, are studied. The drain current and effective mobility decrease after irradiation, while the threshold voltage increases in positive direction. The decrease of the mobility is thought to be due to the scattering of channel electrons with the induced lattice defects and also to the decrease of the electron density in the two-dimensional electron gas (2DEG) region.

Degradation of InGaAs pin photodiodes by neutron irradiation

Irradiation damage in 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 influence of the radiation source on device degradation is then discussed by comparison with 1 MeV electrons with respect to the numbers of knock-on atoms and the non-ionizing energy loss (NIEL). The dependence of performance degradation on the radiation source is attributed to the difference of mass and the probability of nuclear collision for the formation of lattice defects.

IMPACT OF HIGH ENERGY PARTICLE IRRADIATION ON THE ELECTRICAL PERFORMANCE OF SI1-XGEX EPITAXIAL DIODES

The impact of 20-MeV alpha ray irradiation on the electrical characteristics of strained-layer epitaxial Si1−xGex diodes is investigated as a function of fluence and Ge content (x = 0.08, 0.12 and 0.16). The reverse current at a fixed bias increases with fluence, although the rate of increase decreases with increasing fluence and/or Ge content. The reduction of the capacitance with fluence points to a strong deactivation of the boron (B) dopant atoms, which decreases with increasing Ge content. The close to square root dependence between the B-deactivation and the reverse current increase, suggests that in the irradiated diodes the latter is dominated by deep levels associated with interstitial B complexes. This is confirmed by deep level transient spectroscopy, revealing that the trap introduction rate at a given fluence reduces with increasing Ge content, similar to that for the reverse diode current.

Radiation damage of InGaAs photodiodes by high energy particles

Results are presented of a study on the performance degradation and the induced lattice defects of In{sub 0.53}Ga{sub 0.47}As p-i-n photodiodes, subjected to 220-MeV carbon particles. The effects on both the dark current and the photo-current are investigated as a function of the carbon fluence and correlated with DLTS results. The device degradation is compared with the one observed after exposure to 1-MeV electrons, 1-MeV fast neutrons and 20-MeV alpha rays, respectively. The differences in damage coefficients will be explained in view of the calculated number of knock-on atoms and the nonionizing energy loss (NIEL). The recovery behavior of the diode performance and of the induced deep levels by isochronal annealing is also reported.

Radiation damage of In0.53Ga0.47As photodiodes by high energy particles

The performance degradation of In0.53Ga0.47As p-i-n photodiodes, subjected to a 220-MeV carbon particle irradiation in the fluence range 1010 to 1013 cm−2, is reported. It is shown that the increase of the dark current scales roughly with the displacement damage created in the n-type InGaAs region. The degradation of the photo-current, on the other hand, does not scale with the displacement damage, for all irradiations studied. Therefore, it is believed that the photo-current suffers from increased surface recombination, which is related to the ionization damage created in the passivation layer.

Degradation and recovery of Si diodes by 20-MeV protons and 220-MeV carbon particles

Results are presented of a study on the degradation of the electrical performance of Fe contaminated n{sup +}p Si diodes, subjected to a 220-MeV carbon irradiation. The reverse current of the diodes increases after irradiation, while the capacitance and hence the doping concentration decreases. The areal and peripheral components of the leakage current are extracted from diodes with different area to perimeter ratios. Both the generation and the recombination lifetime calculated from I/V and C/V characteristics also decrease. The deep levels in the Si substrate induced by the irradiation are mainly responsible for the degradation of the diode performance. The radiation damage is also studied for 1-MeV electrons and 1-MeV fast neutrons. The performance degradation for carbon irradiation is three orders of magnitude larger than that for electron irradiation. The differences in the radiation damage are explained by the differences in the number of knock-on atoms and the nonionizing energy loss (NIEL), which is attributed to the difference of mass and the possibility of nuclear collision with target Si atoms.

Substrate effects on the degradation of irradiated Si diodes

Irradiation damage in n/sup +/p and p/sup +/n Si diodes by 1-MeV fast neutrons and 1 to 2-MeV electrons is studied as a function of type of Si substrate and radiation source. The degradation of the electrical performance of diodes by irradiation increases with increasing fluence and is much larger for CZ-Si diodes than for FZ-Si diodes. The difference of radiation damage is thought to be due to the formation of lattice defects which are associated with the creation of oxygen related complexes. The degraded performance recovers by thermal annealing. The activation energy of reverse current recovery of n/sup +/p Si diodes irradiated by neutrons with a fluence of 1/spl times/10/sup 13/ n/cm/sup 2/ is calculated to be 0.35 and 0.19 eV.