Radiation Source Dependence Research Articles

Effect of gate interface on performance degradation of irradiated SiC-MESFET

The radiation damages and their degradation mechanism of device performance on 4H-SiC Metal Schottky Field Effect Transistors (MESFETs), which have been irradiated at room temperature with 2 MeV electrons and 20 MeV protons, is studied together with recovery behavior. No performance degradation is observed by 1×10 12 e/cm 2 and 5×10 11 p/cm 2, while a slight increase of the linear drain current together with a decrease of the threshold voltage are noticed above higher fluence. The damage coefficient for protons is about three orders of magnitude larger than that for electrons. The radiation source dependence of the device performance degradation is attributed to the difference of mass and the possibility of nuclear collision for the formation of lattice defects. Based on thermal annealing results of electron-irradiated MESFETs, it is found that the recovery of the drain current characteristics principally takes place from 100 °C, and that the drain current recovers to the pre-rad value after 200 °C annealing, while capacitance and induced deep levels do not recover. From the results annealing behavior with 0.27 eV, it is concluded that the degradation of the drain current is mainly sensitive to the decrease of the Schottky barrier height at the gate contact.

Degradation of SiC-MESFETs by irradiation

The impact of radiation source dependence on the device performance degradation of 4H-SiC MESFETs (Metal Schottky Field Effect Transistors), which have been irradiated at room temperature with 2-MeV electrons and 20-MeV protons, is studied. The damage coefficient for protons is about three orders of magnitude larger than that for electrons. The radiation source dependence of the device performance degradation is attributed to the difference of mass and the possibility of nuclear collision for the formation of lattice defects. From thermal annealing of electron-irradiated MESFETs, it is found that the recovery of the drain current characteristics principally takes place from 100 °C, and that the drain current recovers to the pre-rad value after 200 °C annealing. It is concluded that the degradation of the drain current is mainly sensitive to the radiation-induced decrease of the Schottky barrier height at the gate contact.

Radiation source dependence of device performance degradation for 4H-SiC MESFETs

The impact of radiation source dependence on the device performance degradation of 4H-SiC MESFETs (Metal Schottky Field Effect Transistors), which have been irradiated at room temperature with 2 MeV electrons and 20 MeV protons, is studied. No performance degradation is observed by 1×10 15 e/cm 2 and 5×10 11 p/cm 2 , while a slight increase of the linear drain current together with a decrease of the threshold voltage are noticed above higher fluence . The damage coefficient for protons is about three orders of magnitude larger than that for electrons. The radiation source dependence of the device performance degradation is attributed to the difference of mass and the possibility of nuclear collision for the formation of lattice defects. Based on thermal annealing results of electron-irradiated MESFETs, it is found that the recovery of the drain current characteristics principally takes place from 100 ∘ C, and that the drain current recovers to the pre-rad value after 200 ∘ C annealing. On the other hand, capacitance and induced deep levels do not recover by 200 ∘ C annealing. It is concluded that the degradation of the drain current is mainly sensitive to the radiation-induced decrease of the Schottky barrier height at the gate contact.

Radiation source dependence of performance degradation in thin gate oxide fully-depleted SOI n-MOSFETs

The degradation of the electrical performance of thin gate oxide fully depleted SOI n-MOSFETs and its dependence on the radiation particles are investigated. The transistors are irradiated with 7.5-MeV protons and 2-MeV electrons at room temperature without bias. The shift of threshold voltage and the coupling effect with the degraded opposite gate are clarified. A remarkable reduction of the floating body effects is observed after irradiation. The degradation of the extracted parameters is discussed by a comparison with the damage coefficients.

Model for the radiation degradation of polycrystalline silicon films

The degradation of polycrystalline silicon (Poly-Si) films, subjected to 20-MeV alpha-ray irradiation, is studied. To investigate the radiation source dependence, 20-MeV proton and 1-MeV electron irradiation have been performed as well. The damage of alpha-rays is one and three orders of magnitude larger than for protons and electrons. The radiation source dependence of the performance degradation is attributed to the difference of mass and the probability of nuclear collisions for the formation of lattice defects. It is concluded that the combination of the induced lattice defects in the grain itself and the interface state density at its boundary are mainly responsible for the degradation of the Poly-Si films by high-energy particle irradiation. The degradation of the Poly-Si films can also be explained by a finite grain-bulk dynamic resistance r/sub c/ and a large-barrier dynamic resistance r/sub SCR/ based on the Schottky barrier diode degradation mechanism.

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

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 neutron irradiation on optical performance of InGaAsP laser diodes

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 In0.76Ga0.24As0.55P0.45 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 In0.76Ga0.24As0.55P0.45 multi-quantum well active region are observed after a 1×1016 n/cm2 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 1×1015 n/cm2 after a 300°C annealing.

Radiation damage in Si1−x Ge x heteroepitaxial devices

Results are presented of an extended study on the induced lattice defects and their effects on the degradation of Si1−xGe x devices, subjected to a 20 MeV alpha-ray, 1 MeV electron, 1 MeV fast neutron, and 20 and 86 MeV proton irradiations. The degradation of the electrical device performance increase with increasing fluence, while it decreases with increasing germanium content. In the Si1−xGe x epitaxial layers, electron capture levels associated with an interstitial-substitutional boron complex are induced. 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.

Effect of irradiation in InGaAs photo devices

Results are presented of an extended study on the degradation of electrical and optical performance and the induced lattice defects of In0.53Ga0.47As p-i-n photodiodes, subjected to a 20 MeV alpha-ray irradiation. The difference in radiation damage with 1 MeV fast neutrons and 1 MeV electrons is discussed taking into account the energy transfer. 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.

Radiation damage in InGaAs photodiodes by 1 MeV fast neutrons

Abstract Irradiation damage in In 0.53 Ga 0.47 As p-i-n photodiodes by 1 MeV fast neutrons has been studied as a function of fluence for the first time, and the results are discussed in this paper. The degradation of the electrical and optical performance of diodes increases with increasing fluence. The induced lattice defects in the In 0.53 Ga 0.47 As epitaxial layers and the InP substrate are studied by Deep Level Transient Spectroscopy (DLTS) methods. In the In 0.53 Ga 0.47 As epitaxial layers, hole and electron capture levels are induced by irradiation. The influence of the type of radiation source on the 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). The radiation source dependence of performance degradation is attributed to the difference of mass between the two irradiating particles and the probability of nuclear collision for the formation of lattice defects.

Degradation of SiGe devices by proton irradiation

The degradation and recovery behavior of strained Si 1− x Ge x diodes and heterojunction bipolar transistors (HBTs) irradiated by protons are studied. The degradation of device performance and the generation of lattice defects are reported as a function of fluence and also compared extensively with previous results obtained on electron and neutron irradiated devices. The radiation source dependence of the degradation is discussed taking into account the number of knock-on atoms and the nonionizing energy loss (NIEL).

Degradation and recovery of proton irradiated Si/sub 1-x/Ge/sub x/ epitaxial devices

Irradiation damage in n/sup +/-Si/p/sup +/-Si/sub 1-x/Ge/sub x//n-Si epitaxial diodes and heterojunction bipolar transistors (HBTs) by protons is studied as a function of germanium content, proton fluence and energy for the first time. The degradation of the electrical performance of devices increases with increasing fluence, while it decreases with increasing germanium content and energy. The induced lattice defects in the Si/sub 1-x/Ge/sub x/ epitaxial layers and the Si substrate are studied by DLTS methods. In the Si/sub 1-x/Ge/sub x/ epitaxial layers for diodes, electron capture levels associated with interstitial boron complex are induced by irradiation, while two electron capture levels corresponding to the E center and the divacancy are observed in the collector region of the HBTs. The influence of the radiation source on device degradation is then discussed taking into account the number of knock-on atoms and the nonionizing 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. In order to examine the recovery behavior, isochronal thermal annealing is carried out for temperatures ranging from 75 to 300/spl deg/C. Based on the recovery of electrical performance, it is pointed out that the electron capture levels induced in the Si/sub 1-x/Ge/sub x/ epitaxial layers are mainly responsible for the increase of reverse diode current.

Degradation and Recovery of Si1−xGex Devices by Irradiation

ABSTRACTResults are presented of a study on the degradation and recovery behavior of strained Si 1−xGex 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.