T Hakata

Impact of 20-MeV /spl alpha/-ray irradiation on the V-band performance of AlGaAs pseudomorphic HEMTs

The irradiation damage in Si-planar-doped AlGaAs pseudomorphic HEMTs integrated in 50 GHz monolithic microwave integrated circuits (MMICs) and subjected to 20-MeV /spl alpha/ and /spl gamma/-ray irradiation is studied. Both the static and the high frequency device parameters have been analyzed. It is shown that the drain current and the effective mobility decrease after irradiation, while the threshold voltage shifts in a positive direction. The degradation of the device performance increases for higher fluence. The decrease of the mobility is thought to result from the scattering of channel electrons by the induced lattice defects and also from the decrease of the electron density in the two dimensional electron gas (2DEG) region. Moreover, the noise figure increases with increasing fluence, while the gain decreases. After 150/spl deg/C post-irradiation thermal annealing for 15 min, the noise figure and gain for 1/spl times/10/sup 12/ /spl alpha//cm/sup 2/ recovers by 67 and 19%, respectively.

Degradation and recovery of AlGaAs/GaAs p-HEMT irradiated by high-energy particle

Abstract Results of an extensive study on the irradiation damage and its recovery behavior resulting from thermal annealing in AlGaAs/GaAs pseudomorphic high electron mobility transistors (HEMTs) subjected to a 220-MeV carbon, 1-MeV electrons and 1-MeV fast neutrons are presented. The drain current and effective mobility decrease after irradiation, while the threshold voltage increases in positive direction. The decrease of the drain current and 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 region. Isochronal thermal annealing shows that the device performance degraded by the irradiation recovers. The decreased drain current for output characteristics recovers by 75% of pre-rad value after 300°C thermal annealing for AlGaAs HEMTs irradiated by carbon particles with a fluence of 1×10 12 cm −2 . The influence of the materials and radiation source on the degradation is also discussed with respect to the nonionizing energy loss. Those are mainly attributed to the difference of particle mass and the probability of nuclear collision for the formation of lattice defect in Si-doped AlGaAs donor layer. A comparison is also made with results obtained on irradiated InGaP/InGaAs p-HEMTs in order to investigate the effect of the constituent atom. The damage coefficient of AlGaAs HEMTs is also about one order greater than that of InGaP HEMTs for the same radiation source. The materials and radiation source dependence of performance degradation is mainly thought to be attributed to the difference of mass and the possibility of nuclear collision for the formation of lattice defects in Si-doped donor layer.

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.

Radiation damage in AlGaAs/GaAs pseudomorphic HEMTs

The degradation of AlGaAs/GaAs pseudomorphic HEMTs by 220-MeV carbon, 1-MeV electron and neutron irradiation and their recovery by subsequent isochronal annealing are investigated and compared with results obtained on irradiated InGaP/InGaAs p-HEMTs.

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.

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.

Degradation of MOSFETs on SIMOX by irradiation

Results are presented of a study on the degradation and recovery of the electrical performance of MOSFETs processed on SIMOX substrates, subjected to 1 and 2 MeV electron and to 20 MeV alpha-ray irradiations. The damage coefficient for alpha-ray irradiation is about three orders of magnitude larger than the one for electron irradiation, which is attributed to the difference of incident particle mass and the possibility of nuclear collision during radiation damage.

Radiation source dependence of degradation in MOSFETs on SIMOX substrate

Results are presented for the first time of a study on the degradation of the electrical performance of MOSFET`s processed on SIMOX substrates and subjected to a 220-MeV carbon irradiation. For the n-MOSFETs an unstable increase of the drain current in linear operation is found, while for the p-MOSFETs a drastic reduction is observed, both in linear operation and in saturation. The radiation damage is also compared to the results for 1-MeV electrons, 1-MeV fast neutrons and 20-MeV alpha rays. The differences in the damage coefficients are explained by the differences in the number of knock-on atoms and the nonionizing energy loss (NIEL). The recovery behavior of the device performance by isochronal annealing is also reported.

Degradation and Recovery of Si 1−x Ge x Devices by Irradiation

Results are presented of a study on the degradation and recovery behavior of strained Si 1−x Ge x diodes and heterojunction bipolar transistors (HBTs) by electron and neutron irradiation. The degradation of device performance and the generation of lattice defects are reported as a function of germanium content and radiation source. Isochronal annealing is performed to study the recovery behavior of the irradiated devices. The radiation source dependence of the degradation is discussed taking into account the absorbed energy dunng irradiation.