Haider F. Abdul Amir

Evaluation on Diffusion of Bipolar Junction Transistor (BJT) Charge-Carrier and its Dependency on Total Dose Irradiation

Electronic device that subjected to various effects by radiations can cause small interferences such as noises in the circuit. These effects are especially critical in operating environment such as outer space, where radiation comes in stronger and more frequent. In this research, analytical study on the effects of ionizing radiation induced by 60Co gamma (γ) rays in bipolar junction transistor (BJT) devices had been performed. It was found that the high energy of the radiation allows more valence electrons to be excited to the conduction band in the BJT. This leads to the production of a large number of excited atoms and increases the holes in the valence band. The increase of holes in the base region due to trapping will increase the probability of recombination and reducing the number of electrons that reaches the collector region. This ionizing radiation effect was found to arouse either a permanent or temporarily damage in the devices depending on their current drives and total dose absorbed.

Range distribution and electronic stopping power for Cobalt (Co) ions in Gallium Arsenide (GaAs) optoelectronic devices

Studies for introduction of atoms into a solid substrate by bombardment of the solid with ions in the electron-volt (eV) to mega-electron-volt (MeV) energy range have always received great interest. Gallium Arsenide (GaAs) is a basic material for most of the III-V based electronics, and, therefore, lends itself for applications where this is of concern. In this paper, the damage evolution due to photon energy deposition of Cobalt (Co) is being simulated in GaAs material using SRIM (Stopping and Range of Ions in Matter). Besides, TRIM (The Range of Ions in Matter) calculation also gives the amount of nuclear energy deposited in the collisions and recoil events. From the findings of this research, it is found that exposure to high energy photon irradiation causes a degradation of the electrical parameters of GaAs layer and this is mainly caused by the displacement damage.

Effects of high energy neutrons and resulting secondary charged particles on the operation of MOSFETs

Study for penetration of nuclear radiation into semiconductor materials had been of theoretical interest and of practical important in these recent years, driven by the scaling down of semiconductor materials. This paper reviews the typical effects occurring in the operation of MOSFETs due to irradiation with neutrons resulting from Deuterium-Tritium (D-T) reaction. Charge trapping features of MOSFETs were investigated by in situ irradiation and post irradiation methods. Analytical explanations and calculations on the numeric change that occurs in the MOSFETs were conducted using a series of simulations. The oxide insulating layer of MOSFET is found to be most sensitive to the neutron radiation. Energy deposition of neutrons in MOSFET occurs via two mechanisms; firstly by trapped charge buildup in the silicon dioxide (SiO2) layer and secondly, an increase in the density of trapping states at the SiO2 interface. The bombardment of neutron in the MOSFET model produces at least three secondary particles, which are alpha (α) particles, proton (p) particles and silicon recoil atoms, through the reactions of (n,α), (n,p) and neutron scattering respectively. Damage efficiencies of these secondary particles are discussed in direct comparisons.

Defect Generation in Bipolar Devices by Ionizing Radiation

This paper reviews typical effects occurring in bipolar junction transistors (BJTs) due to gamma (γ) rays irradiation. The detrimental consequences of this interaction can be categorized into two: the transfer of energy to electrons due to ionization and electronic excitations; and also the transfer of energy to atomic nuclei. The radiation damage induced by this interaction was studied using in situ method by comparing the currentvoltage characteristics of the devices under test (DUTs) at different biased collecting current and operating modes. The high energy from gamma radiation is found to induce both temporarily and permanent damage in the DUTs depending on the current drive and total dose absorbed. The most significant radiation damage in the BJT is the creation of electron-hole pairs which increases the probability of recombination at the base region of BJTs. The DUTs are found to exhibit minor annealing effect at post-irradiation and the results also show that devices operating in higher bias current are more capable of withstanding the effect by gamma radiation.

Monte Carlo Simulation of Alpha (α) Particles Penetration in Nanoscale Silicon Semiconductor Materials

Microsystems, both in space and ground level, will use systems with III-V semiconductors and devices of nanoscale. Vulnerability of this system towards the radiations warrants extra care to be taken. Therefore, appropriate test and analysis to assure the hardness (radiation resistance) of components to be used in various radiation environments is necessary. In this paper, the defect generated in the interaction of alpha (α) particles and silicon (Si) semiconductor material is simulated using SRIM (Stopping and Range of Ions in Matter). The induced defects are in the form of vacancies, defect clusters and dislocations. Besides, the defect is found influencing the kinetic processes that occur both inside and outside the cascade volume. The radiation tolerance between the conventional scale and nanoscale thickness of silicon layer is also being compared. From the findings, it is observed that when the thickness of silicon layer is scaled down, defect that induced by the energy deposition of -particles is significantly lesser. This means that nanoscale silicon layer features improved radiation robustness towards the deposition of energetic ions.

Monte Carlo study of alpha (α) particles transport in nanoscale gallium arsenide semiconductor materials

Space and ground level electronic equipment with semiconductor devices are always subjected to the deleterious effects by radiation. The study of ion-solid interaction can show the radiation effects of scattering and stopping of high speed atomic particles when passing through matter. This study had been of theoretical interest and of practical important in these recent years, driven by the need to control material properties at nanoscale. This paper is attempted to present the calculations of final 3D distribution of the ions and all kinetic phenomena associated with the ions energy loss: target damage, sputtering, ionization, and phonon production of alpha (α) particle in Gallium Arsenide(GaAs) material. This calculation is being simulated using the Monte Carlo simulation, SRIM (Stopping and Range of Ions in Matter). The comparison of radiation tolerance between the conventional scale and nanoscale GaAs layer will be discussed as well. From the findings, it is observed that most of the damage formed in...

Simulation of ionizing radiation induced effects in nanoscale semiconductor material

Study for defect in semiconductors induced by ionizing radiation has become much more sophisticated in this recent year, driven by the current development in the ongoing miniaturization of silicon (Si) semiconductor industry. In this paper, the damage evolution due to Cobalt-60 (Co-60) is being simulated in nanoscale Silicon layer using SRIM (Stopping and Range of Ions in Matter). SRIM is a computer simulation that uses Monte Carlo method and it contains TRIM (The Range of Ions in Matter) calculation. The SRIM-TRIM calculates the range of ions in matter using collisions of ions-atoms. Besides, the radiation tolerance of the silicon layer is compared when its thickness is scaling down to nano dimension. From the findings, it is observed that the penetration of Co-60 ions into the target silicon layer leads to production of lattice defects in the form of vacancies, defect clusters and dislocations. These can alter the material parameters and hence the properties of the devices. The simulation results also show that nanoscale silicon layer features improved radiation robustness against ionizing radiation, in term of displacement damage.

Calculation of the Rate of Helium Ion Dispersion in Gallium Arsenide Compound

Nuclear dispersion is an important aspect in the process of slowing down ions by transferring their momentum to the target atoms and in determining path of the ion. This paper concerns the quantitative evaluation of the mechanism at which helium ions lose their energy when penetrate into a solid and the eventual distribution of the helium ion while stopping inside the Gallium Arsenide compound (GaAs). The first order effects of the atoms of the compound such as the electronic excitation of the atom, the lattice damage incurred to it, as well as the production of phonons in Gallium Arsenide due to the helium ions are also taken into account. The main finding is the mechanism of penetration of helium ions in GaAs, which is affected by the energy, the angle of incidence, and penetration density of the helium ions. It is found out that the energy has major impact than the angle of incidence in the interaction.

Evaluation of static performance of optoelectronic semiconductor devices under X-rays irradiation

In this research, optoelectronic devices consisted of an infrared light emitting diode and a phototransistor with no special handling or third party-packaging were irradiated to ionizing radiation utilizing x-rays. It was found that the devices under test (DUTs) undergo performance degradation in their functional parameters during exposure to x-rays. These damaging effects are depending on their current drives and also the Total Ionizing Dose (TID) absorbed. The TID effects by x-rays are cumulative and gradually take place throughout the lifecycle of the devices exposed to radiation.

A model for neutron radiation damage in Metal Oxide Semiconductor (MOS) structures

Neutron bombardment on semiconductor material causes defects, one such primary physical effect is the formation of displacement defects within the crystal lattice structure, and such defects effectively decrease the mean free path and thus shorten the recombination time. Ionizing radiation causes creation of electron-hole pair in the gate oxide and in parasitic insulating layers of the MOS devices. Calculations show increase of the dark current in depletion region caused by a single neutron. Determination of energy and angular distribution of primary knock on atoms, with 14 MeV neutron irradiation in silicon are presented.