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The local order in Plasma-Enhanced Chemical Vapor Deposition (PECVD) N-rich a-SiNx:H films is shown to depend strongly on the H bonding configuration. The SiH bonding affects the SiN lattice vibration, giving a shoulder at 1020 cm−1, and shifts the Si3p - N2p peak position in the valence band distribution towards lower binding energies.

CNX thin films have been deposited on Si(100) substrates using a new hybrid deposition system. This system combines excimer laser ablation of a graphite target and an atomic nitrogen source from a remote surface wave plasma. The films were characterized using X-ray photoelectron spectroscopy (XPS), elastic recoil detection (ERD) and Fourier transform infrared spectroscopy (FTIR). We found that the atomic nitrogen source enhances the incorporation of N in the CNxlayers, for example, from N/C = 0.04 (plasma off) to 0.18 (plasma on). In addition, as nitrogen pressure in the deposition chamber is increased from 2mTorr to 1 Torr, the N/C ratio increases from 0.18 to 0.56. The XPS and FTIR spectra indicate that at deposition pressures above 100 mTorr, nitrogen incorporation is enhanced through the formation of hydrogenated carbon nitride groups, while at lower pressures, only simple and double CN bonds are detected.

The level structure of theN=80,140Nd has been investigated through the beta decay of140mPm and140gPm, whose decay half-lives were measured to be 5.95±0.05 min and 9.1±0.5 sec, respectively. Decay schemes for the two isomers have been constructed from?-ray measurements. With the help of the beta decayft values and internal conversion electron measurements, spins and parities were deduced for levels in140Nd. Among the levels a 7- state at 2222.0 keV and a 5- state at 2273.3 keV are identified as two-neutron quasiparticle states. The (ie233-01) for140mPm and140gPm have been deduced as 7- and 1+, respectively. From beta end-point measurements, the decay energies of the two isomers have been determined asQEC=6.48±0.07 MeV140m(Pm) andQEC=6.08±0.10 MeV (140gPm). The results are discussed in the light of nuclear systematics of theN=79 and 80 isotones.

The structure of140Pm is investigated through the beta decay of140Sm, whose half-life is measured to be (14.7 ± 0.2) m. A level structure comprising 41 transitions among 17 excited states is constructed. Using the deduced ft values and measured internal conversion coefficients, spin-parity assignments to several states in140Pm were made. From beta end-point measurement, the total decay energy is deduced to beQEC=3.4±0.3 MeV, which is compared with the predictions of several mass formulae. The systematics of the odd-Z, N=79 isotones are discussed.

The structure of139Sm is investigated through the decay properties of139mSm and139Eu. The decay of139mSm is measured to have a half-life of (10.7±0.6) s. Gamma-ray and internal conversion electron measurements lead to the construction of a decay pattern comprising seven transitions among five states. The decay of139Eu with a measured half-life of (17.9± 0.6) s is studied with beta decay spectroscopy techniques. A decay scheme consisting fourteen states in139Sm is proposed. Using deducedft values and transition multipolarities,Jρ assignments are made. Nuclear systematics of the odd-A, N=77 and 76 are discussed.

The structure of138Nd is investigated through theß+-decay of138Pm, whose decay half-life is measured to be 3.24±0.05 min. A level structure comprising 27 excited states and 52 transitions is constructed. With the help of deducedft values and internal conversion coefficients, spin-parity assignments are made to many states in138Nd and to the ground states of138Pm. From the positron end-point energy measurement, the total decay energy is determined to be 5.4±0.2 MeV, which is compared with the predictions of several mass formulae and with the decay energy systematics of theN=77 isotones. The structure of138Nd is discussed in the light of nuclear systematics of theN=78 isotones.

The nuclide141Eu is identified to have two beta decaying isomers,141gEu and141mEu, whose decay half-lives are measured to be 40.0±0.7 s and 3.3±0.3s, respectively. Their decay properties are studied by means of beta and gamma spectroscopy techniques. The states withJp assignments in141Sm thus deduced are compared with those of the other odd-A, N=79 isotones. The total decay energy of141gEu is measured to be 6.03±0.10 MeV, which is compared with the predictions of several mass formulae and with the decay energy systematics of theN=78 isotones. The141gEu and141mEu are deduced to haveJp=5/2+ and 11/2-, respectively. A 96.4 keV isomeric transition between them is found to be anE3 transition with aB(E3)=1.6±0.4e2fm6. The structure of141Eu is compared with that of the otherN = 78 isotones.

Hydrogenated boron thin films have been deposited at temperatures in the range 50–100 °C with the radiofrequency plasma decomposition of diborane B2H6diluted in hydrogen. The chemical composition of the films has been determined by elastic recoil detection and by the Castaing microprobe techniques. We have found that the as-deposited films contain 10–20 at % H and that they react with the ambient atmosphere within a few days and reach a final composition close to B0.64H0.12O0.12C0.06N0.06. The optical properties of the as-deposited films studied by spectroscopic phase-modulated ellipsometry in the range 1.7–5.0 eV are characteristic of the high optical gap semiconductors. The electron diffraction measurements performed onin situannealed samples show that the films are amorphous up to 950 °C. Infrared spectroscopy investigations performed on the as-deposited films have revealed two hydrogen bonding sites: B-H terminal bonds and B-H-B bridge bonds, along with some B-O-B groups. Upon exposure to the atmosphere, the vanishing of B-H-B and B-O-B bridge bonds and the increase of B-H and B-O-H absorption bands after 1 day, are observed.

The decay characteristics of 19 min126mSb have been studied using Ge(Li) and scintillation spectrometers. The sources of126mSb were obtained by the (n, p) reaction on enriched126Te. The gamma rays of energies 414.4±0.3, 666.7±0.5 and 696.1±0.5 keV were found decaying with a half-life of 19 min. The study of beta spectra employing an anthracene crystal yielded two beta groups with end-point energies of 1.9±0.15 and 2.5±0.15 MeV. The results of singles and coincidence measurements have been incorporated into a decay scheme with excited states of126Te at 666.7, 1,362.8 and 1,777.2 keV.

The positron decay of144Eu is reinvestigated using beta- and gamma-ray spectroscopy techniques. A decay scheme comprising three excited states and four transitions in144Sm is constructed. Three new transitions are observed and have led to the establishment of a second 2+ state populated in this decay. The half-life of144Eu has been accurately measured to be 10.2±0.1 s. Spin-parity assignments are made to all the levels involved in the decay. The structure of144Sm is discussed in the light of different models.

The electromagnetic decay of the 11/2−141mSm is investigated. Internal conversion electron and X-ray-conversion electron coincidence measurements indicate that the state undergoesβ+ and electron capture decay with 99.69% strength and the remaining 0.31% goes to a 174.2±0.3 keVM4 transition. TheK/L conversion electron intensity ratio for the transition is measured to be 1.7±0.4. The energy of the 11/2− is established at 175.8±0.3 keV above the 1/2+ ground state in141Sm. Systematics of theM4 transitions in theN=79 and 81 isotones are discussed.

Thin films of silicon oxynitrocarbide (SiONC)have been deposited on silicon by polymer-source chemical vapor deposition (PSCVD) using poly(dimethylsilane). The chemical and structural composition of these films have been investigated using Fourier transform infrared spectroscopy, elastic recoil detection spectroscopy (ERD), and X-ray photoelectron spectroscopy (XPS). ERD depth-profile analysis revealed a homogeneous film with uniform bulk concentrations for silicon, carbon, nitrogen, and oxygen. XPS analysis showed that nitrogen, oxygen, and carbon were all uniquely bonded to silicon. The oxygen nitrogen bonds were not observed in these films. XPS analysis also revealed the presence of carbon-carbon bonds associated with graphite. It was shown that the graphitic phase is limited to the surface layer of these films, and is due to unintentional carbonization at the end of the deposition process. The relatively low bulk atomic concentration of carbon in the SiONCthin films (∼1%)render these films a possible alternative to SiON, and could become very attractive for the fabrication of integrated optical waveguides, and as a dielectric material in variety of microelectronic and optoelectronic devices.