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4966. Effect of ion implantation on CdSe thin film transistors
Classified
abstracts
49634972
susceptibility measurements of bubble garnet implanted with 100 keV Ne’ ions. The dose- and annealing dependent behaviour is examined, specifically the effects resulting from shifts in the layer’s ordering temperature. such as early indications of overdamage and increases in the anisotropy after annealing. (Canada) I Maartense et al. J Appl Phys, 52 (3). 1981, 2361-2363. 35 4963. Implantability of small bubble diameter garnet films. (USA) Measurements of anisotropy in implanted bubble films indicate that in addition to straining the lattice, implantation also has the effect of suppressing the growth-induced anisotropy. After annealing at lOOo”C, most of the as-grown anisotropy is restored, which points to oxygen defects as the most likely mechanism for the effect. The Curie temperature has been found to be lowered by as much as 70°C by implantation at a typical devtce dose. and the anisotropy of the implanted layer varies quite rapidly with temperature at elevated temperatures. The results indicate that with proper choice of material parameters and implantation conditions satisfactory bubble propagation can be obtained in high density small bubble diameter devices based on ion-implanted propagation patterns over a wide temperature range. G P Vella-Coleiro et al, J Appl Phys, 52 (3), 1981, 2355-2357. 35 4964. Laser annealing of epitaxial garnet films under controlled atmospheres. (USA) Epitaxial films with a composition of Eu,,,,Y,,,,Pb,,,Fe,.,,Ga,,,,O,, have been laser annealed in forming gas, nitrogen, air and oxygen. Annealed films were studied using bubble statics, ferromagnetic resonance and X-ray techniques. Changes in the annealing ambient resulted in variations in the maximum saturation magnetization (4nM,) achieved, and in the laser power thresholds for film cracking and melting. In comparison with other atmospheres. oxygen allowed the use of greater laser power without film damage and yielded the highest saturation magnetization. The increase in 4nM, (above the as-grown value) produced by annealing in oxygen was more than 30% larger than achieved in air and more than 507, larger than reached in forming gas or nitrogen. The influence of an ambient is interpreted in terms of its ability to suppress the formation of oxygen vacancies during laser annealing. D A Herman Jr et al, J Appl Phys. 52 (3). 1981, 2341-2343. 35 4965. Laser annealing and epitaxy. (USA) Epitaxial reordering of disordered surface layers is accomplished during laser or electron beam annealing by growth from either the solid or the liquid phase. Both processes yield homoepitaxial layers of excellent quality on silicon. The solid-phase-epitaxial process (SPE) is analogous to that obtained by furnace heating and is applicable to implantation damaged surface layers, The process. however, is completed within milliseconds by beam processing, and impurity diffusion is insignificant. Liquid-phase-epitaxial growth (LPE) occurs during resoliditication of the flash melted surface and is applicable to deposited overlayers as well as to implantation damaged layers, In this process, impurity diffusion within the liquid film and segregation at the crystallization front are responsible for impurity redistribution. Metastable solutions of extraordinary solute concentration may be fabricated by the (LPE) process. H J Leamy, J Vat Sri Technol. I8 (2), 1981. 2088214. 35 4966. Effect of ion implantation on CdSe thin film transistors. (USA) Thin film transistors have been fabricated by implanting 50 keV Cr. 50 keV Al. and 15 keV Bions into high resistivity (1 10s Rem), polycrystalline CdSe deposited by thermal evaporation. The implants were made at room temperature into inverted transistor structures fabricated by photoengraving. Both the Cr and Al implants cause a maximum decrease of approximately l.S”10 in the c-axis lattice spacing of CdSe. and enhance the (00.1) texture of the grains. Similar but smaller changes in c were observed in B implanted samples. For a fixed CdSe film thickness of z 800 A, the rapidly with implant dose above the drain current, I,. increases unimplanted value (- 10 nA). At a dose of 5 x lOI cm-‘, I, was annroximatelv 200 uA (V, = 10 V, V, = 10 V) for the Cr and B implants bu; was much higher for AT: ID was 1.9 mA at V, = 0.5 V for the same I/,. The current-dose dependence is interpreted in terms of filling of grain boundary traps by implanted donors, with the intergrain potential barrier height determined by- the implant dose. (Canada) F R Shepherd et al, J Vat Sci Techno/, I8 (3). 1981, 899-902. 218
35 4967. Detection of residual damage in 75As implanted silicon single crystal by secondary ion mass spectrometry. (USA) Radiation damage occurred in single crystalline silicon during “As ion implantation at 50 keV and could not be annealed out completely at 1OOO’C for 30-70 min. Part of the damaged volume was recrystallized by this 1000°C thermal treatment. The other part. with a relatively low level ofdamage, did not recrystallize but acted as a sink for trapping impurities during annealing. In the case of implantation into silicon covered with a thin (225 A) layer of silicon dioxide, secondary ion mass spectrometry showed a different 75As in-depth profile as compared with the case of implantation into bare silicon. Additional annealing, after implantation. was added in both cases. Recoiled oxygen from the SiO, layer segregated into the region with residual damage during thermal annealing and enhanced the ionization yield of “As. The diffusion depth of arsenic was found to be affected by the retained damage and trapped oxygen. A C Yen, J Vat Sci Technol, 18 (3), 1981. 895-898. 35 4968. Microstructure of beam-annealed silicon. (USA) Ion implantation damage in semiconductors can be removed by irradiation with particle beams. Short. energetic photon, ion or electron pulses seem to achieve this effect by inducing a first-order phase change in the near-surface region. The microstructure of pulsed-laser and ion-beam irradiated Si has been studied with transmission electron microscopy, taking advantage of high-resolution and microdiflraction techniques. Laser-irradiated samples, thinned in cross section at pulse-energies near the threshold for epitaxial regrowth, neatly display some features of the nucleation and regrowth phenomena. which are consistent with thermal melting. Some solid-state growth can be seen beneath the presumably melted region, Direct evidence that the melting point of amorphous Si is lower than the crystalline value is also seen. Annealing with ps duration laser pulses is reported. Pulsed ion-beam irradiation is shown to be capable of removing defects, at least within 1 micron of a wafer surface, confirming the promise of this new form of beam-annealing. J M Gibson, J Vat Sci Techrd, 18 (3). 1981, 810817. 35 4969. Ion implanted species dependence in silicon oxidation. (USA) The effect on thermal oxidation of implantation of the alkali species Li, Na, K, Rb and Cs has been studied. A correlation is found with the atomic and ionic radii and atomic masses of the implanted species, the larger ions leading to greater oxidation. We propose that the implanted species may affect the oxide plasticity and that this may be the controlling factor which determines the degree of oxidation. (GB) R A Collins et al, Rad E$ecrs. 58 (3). 1981. 103-108. 35 4970, Pn junction formation in CdTe by ion implantation and pulsed ruby laser annealing. (USA) Cs’ ion implantation followed by Q-switched ruby laser annealing has been used to fabricate a shallow pn junction in n-type CdTe:In. C B Norris et al, Rad Ejects, 58 (3). 1981. 115-l 17. 35 4971. High-purity thermal treatment of silicon. (USA) A specially designed. radio-frequency heated oven made out of polycrystalline silicon has been used for high-purity thermal treatments of silicon at 1200°C. Neutron activation analysis and electron paramagnetic resonance proved that the content of iron and other transition metals could be kept well below 10” cme3. (West Germany) G Borchardt et al. J Appl Phys. 52 (3). 1981, 1063-1064. 35 4972. Defect formation in heavily doped Si upon irradiation. (USA) The rates of the carrier removal and radiation defect (RD) introduction into n- and p-Si in the concentration range of 10i4-10” cm-3 upon 7MeV-electron irradiation have been studied. The spectrum ofthe vacancytype defects, defining the carrier removal rate in lightly doped crystals (no, po-< lOi cm- ‘). has been found. With doping level increase the carrier removal rate grows irrespective of conductivity type, and at n,, p,, > lOi’ cmm3 is close to the total displacement number. At the same time a decrease in the introduction rate of the known vacancy-type defects is observed. It is shown that a considerable growth of the carrier removal rate is defined neither by introduction of shallow compensating centers, nor by change in the primary defect charge state. It is suggested that at high doping impurity concentrations compensation in Si is due to the introduction ofcomplexes doping impurity-interstitial or (impurity atominterstitial + vacancy, which give deep levels (E, > l/2&,). (USSR) V I Gubskaya et al, Rad Efiecrs. 55 (l/Z), 1981. 35-38.
abstracts
49634972
susceptibility measurements of bubble garnet implanted with 100 keV Ne’ ions. The dose- and annealing dependent behaviour is examined, specifically the effects resulting from shifts in the layer’s ordering temperature. such as early indications of overdamage and increases in the anisotropy after annealing. (Canada) I Maartense et al. J Appl Phys, 52 (3). 1981, 2361-2363. 35 4963. Implantability of small bubble diameter garnet films. (USA) Measurements of anisotropy in implanted bubble films indicate that in addition to straining the lattice, implantation also has the effect of suppressing the growth-induced anisotropy. After annealing at lOOo”C, most of the as-grown anisotropy is restored, which points to oxygen defects as the most likely mechanism for the effect. The Curie temperature has been found to be lowered by as much as 70°C by implantation at a typical devtce dose. and the anisotropy of the implanted layer varies quite rapidly with temperature at elevated temperatures. The results indicate that with proper choice of material parameters and implantation conditions satisfactory bubble propagation can be obtained in high density small bubble diameter devices based on ion-implanted propagation patterns over a wide temperature range. G P Vella-Coleiro et al, J Appl Phys, 52 (3), 1981, 2355-2357. 35 4964. Laser annealing of epitaxial garnet films under controlled atmospheres. (USA) Epitaxial films with a composition of Eu,,,,Y,,,,Pb,,,Fe,.,,Ga,,,,O,, have been laser annealed in forming gas, nitrogen, air and oxygen. Annealed films were studied using bubble statics, ferromagnetic resonance and X-ray techniques. Changes in the annealing ambient resulted in variations in the maximum saturation magnetization (4nM,) achieved, and in the laser power thresholds for film cracking and melting. In comparison with other atmospheres. oxygen allowed the use of greater laser power without film damage and yielded the highest saturation magnetization. The increase in 4nM, (above the as-grown value) produced by annealing in oxygen was more than 30% larger than achieved in air and more than 507, larger than reached in forming gas or nitrogen. The influence of an ambient is interpreted in terms of its ability to suppress the formation of oxygen vacancies during laser annealing. D A Herman Jr et al, J Appl Phys. 52 (3). 1981, 2341-2343. 35 4965. Laser annealing and epitaxy. (USA) Epitaxial reordering of disordered surface layers is accomplished during laser or electron beam annealing by growth from either the solid or the liquid phase. Both processes yield homoepitaxial layers of excellent quality on silicon. The solid-phase-epitaxial process (SPE) is analogous to that obtained by furnace heating and is applicable to implantation damaged surface layers, The process. however, is completed within milliseconds by beam processing, and impurity diffusion is insignificant. Liquid-phase-epitaxial growth (LPE) occurs during resoliditication of the flash melted surface and is applicable to deposited overlayers as well as to implantation damaged layers, In this process, impurity diffusion within the liquid film and segregation at the crystallization front are responsible for impurity redistribution. Metastable solutions of extraordinary solute concentration may be fabricated by the (LPE) process. H J Leamy, J Vat Sri Technol. I8 (2), 1981. 2088214. 35 4966. Effect of ion implantation on CdSe thin film transistors. (USA) Thin film transistors have been fabricated by implanting 50 keV Cr. 50 keV Al. and 15 keV Bions into high resistivity (1 10s Rem), polycrystalline CdSe deposited by thermal evaporation. The implants were made at room temperature into inverted transistor structures fabricated by photoengraving. Both the Cr and Al implants cause a maximum decrease of approximately l.S”10 in the c-axis lattice spacing of CdSe. and enhance the (00.1) texture of the grains. Similar but smaller changes in c were observed in B implanted samples. For a fixed CdSe film thickness of z 800 A, the rapidly with implant dose above the drain current, I,. increases unimplanted value (- 10 nA). At a dose of 5 x lOI cm-‘, I, was annroximatelv 200 uA (V, = 10 V, V, = 10 V) for the Cr and B implants bu; was much higher for AT: ID was 1.9 mA at V, = 0.5 V for the same I/,. The current-dose dependence is interpreted in terms of filling of grain boundary traps by implanted donors, with the intergrain potential barrier height determined by- the implant dose. (Canada) F R Shepherd et al, J Vat Sci Techno/, I8 (3). 1981, 899-902. 218
35 4967. Detection of residual damage in 75As implanted silicon single crystal by secondary ion mass spectrometry. (USA) Radiation damage occurred in single crystalline silicon during “As ion implantation at 50 keV and could not be annealed out completely at 1OOO’C for 30-70 min. Part of the damaged volume was recrystallized by this 1000°C thermal treatment. The other part. with a relatively low level ofdamage, did not recrystallize but acted as a sink for trapping impurities during annealing. In the case of implantation into silicon covered with a thin (225 A) layer of silicon dioxide, secondary ion mass spectrometry showed a different 75As in-depth profile as compared with the case of implantation into bare silicon. Additional annealing, after implantation. was added in both cases. Recoiled oxygen from the SiO, layer segregated into the region with residual damage during thermal annealing and enhanced the ionization yield of “As. The diffusion depth of arsenic was found to be affected by the retained damage and trapped oxygen. A C Yen, J Vat Sci Technol, 18 (3), 1981. 895-898. 35 4968. Microstructure of beam-annealed silicon. (USA) Ion implantation damage in semiconductors can be removed by irradiation with particle beams. Short. energetic photon, ion or electron pulses seem to achieve this effect by inducing a first-order phase change in the near-surface region. The microstructure of pulsed-laser and ion-beam irradiated Si has been studied with transmission electron microscopy, taking advantage of high-resolution and microdiflraction techniques. Laser-irradiated samples, thinned in cross section at pulse-energies near the threshold for epitaxial regrowth, neatly display some features of the nucleation and regrowth phenomena. which are consistent with thermal melting. Some solid-state growth can be seen beneath the presumably melted region, Direct evidence that the melting point of amorphous Si is lower than the crystalline value is also seen. Annealing with ps duration laser pulses is reported. Pulsed ion-beam irradiation is shown to be capable of removing defects, at least within 1 micron of a wafer surface, confirming the promise of this new form of beam-annealing. J M Gibson, J Vat Sci Techrd, 18 (3). 1981, 810817. 35 4969. Ion implanted species dependence in silicon oxidation. (USA) The effect on thermal oxidation of implantation of the alkali species Li, Na, K, Rb and Cs has been studied. A correlation is found with the atomic and ionic radii and atomic masses of the implanted species, the larger ions leading to greater oxidation. We propose that the implanted species may affect the oxide plasticity and that this may be the controlling factor which determines the degree of oxidation. (GB) R A Collins et al, Rad E$ecrs. 58 (3). 1981. 103-108. 35 4970, Pn junction formation in CdTe by ion implantation and pulsed ruby laser annealing. (USA) Cs’ ion implantation followed by Q-switched ruby laser annealing has been used to fabricate a shallow pn junction in n-type CdTe:In. C B Norris et al, Rad Ejects, 58 (3). 1981. 115-l 17. 35 4971. High-purity thermal treatment of silicon. (USA) A specially designed. radio-frequency heated oven made out of polycrystalline silicon has been used for high-purity thermal treatments of silicon at 1200°C. Neutron activation analysis and electron paramagnetic resonance proved that the content of iron and other transition metals could be kept well below 10” cme3. (West Germany) G Borchardt et al. J Appl Phys. 52 (3). 1981, 1063-1064. 35 4972. Defect formation in heavily doped Si upon irradiation. (USA) The rates of the carrier removal and radiation defect (RD) introduction into n- and p-Si in the concentration range of 10i4-10” cm-3 upon 7MeV-electron irradiation have been studied. The spectrum ofthe vacancytype defects, defining the carrier removal rate in lightly doped crystals (no, po-< lOi cm- ‘). has been found. With doping level increase the carrier removal rate grows irrespective of conductivity type, and at n,, p,, > lOi’ cmm3 is close to the total displacement number. At the same time a decrease in the introduction rate of the known vacancy-type defects is observed. It is shown that a considerable growth of the carrier removal rate is defined neither by introduction of shallow compensating centers, nor by change in the primary defect charge state. It is suggested that at high doping impurity concentrations compensation in Si is due to the introduction ofcomplexes doping impurity-interstitial or (impurity atominterstitial + vacancy, which give deep levels (E, > l/2&,). (USSR) V I Gubskaya et al, Rad Efiecrs. 55 (l/Z), 1981. 35-38.