| 1. |
- Ding Yuan, Chen, 1991, et al.
(författare)
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Impact of in situ NH3 pre-treatment of LPCVD SiN passivation on GaN HEMT performance
- 2022
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Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 37:3
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Tidskriftsartikel (refereegranskat)abstract
- The impact on the performance of GaN high electron mobility transistors (HEMTs) of in situ ammonia (NH3) pre-treatment prior to the deposition of silicon nitride (SiN) passivation with low-pressure chemical vapor deposition (LPCVD ) is investigated. Three different NH3 pre-treatment durations (0, 3, and 10 min) were compared in terms of interface properties and device performance. A reduction of oxygen (O) at the interface between SiN and epi-structure is detected by scanning transmission electron microscopy (STEM )-electron energy loss spectroscopy (EELS) measurements in the sample subjected to 10 min of pre-treatment. The samples subjected to NH3 pre-treatment show a reduced surface-related current dispersion of 9% (compared to 16% for the untreated sample), which is attributed to the reduction of O at the SiN/epi interface. Furthermore, NH3 pre-treatment for 10 min significantly improves the current dispersion uniformity from 14.5% to 1.9%. The reduced trapping effects result in a high output power of 3.4 W mm(-1) at 3 GHz (compared to 2.6 W mm(-1) for the untreated sample). These results demonstrate that the in situ NH3 pre-treatment before LPCVD of SiN passivation is critical and can effectively improves the large-signal microwave performance of GaN HEMTs.
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| 2. |
- Gard, G, et al.
(författare)
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Stress and qualification of computer work
- 1989
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Ingår i: Work with display units 89: Selected papers from the second international conference of work with display units (Eds. L Berlinguet, D Berthelette.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Gogova, Daniela, et al.
(författare)
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Epitaxial growth of β -Ga 2 O 3 by hot-wall MOCVD
- 2022
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Ingår i: AIP Advances. - : AIP Publishing. - 2158-3226. ; 12:5, s. 055022-055022
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Tidskriftsartikel (refereegranskat)abstract
- The hot-wall metalorganic chemical vapor deposition (MOCVD) concept, previously shown to enable superior material quality and highperformance devices based on wide bandgap semiconductors, such as Ga(Al)N and SiC, has been applied to the epitaxial growth ofβ-Ga2O3. Epitaxial β-Ga2O3 layers at high growth rates (above 1 μm/h), at low reagent flows, and at reduced growth temperatures(740 ○C) are demonstrated. A high crystalline quality epitaxial material on a c-plane sapphire substrate is attained as corroborated by a combination of x-ray diffraction, high-resolution scanning transmission electron microscopy, and spectroscopic ellipsometry measurements. Thehot-wall MOCVD process is transferred to homoepitaxy, and single-crystalline homoepitaxial β-Ga2O3 layers are demonstrated with a 201 ¯rocking curve width of 118 arc sec, which is comparable to those of the edge-defined film-fed grown (201) ¯ β-Ga2O3 substrates, indicative ofsimilar dislocation densities for epilayers and substrates. Hence, hot-wall MOCVD is proposed as a prospective growth method to be furtherexplored for the fabrication of β-Ga2O3
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| 4. |
- Gogova, Daniela, 1967-, et al.
(författare)
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Epitaxial growth of β-Ga2O3 by hot-wall MOCVD
- 2022
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Ingår i: AIP Advances. - : AIP Publishing. - 2158-3226. ; 12:5
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Tidskriftsartikel (refereegranskat)abstract
- The hot-wall metalorganic chemical vapor deposition (MOCVD) concept, previously shown to enable superior material quality and high performance devices based on wide bandgap semiconductors, such as Ga(Al)N and SiC, has been applied to the epitaxial growth of beta-Ga2O3. Epitaxial beta-Ga2O3 layers at high growth rates (above 1 mu m/h), at low reagent flows, and at reduced growth temperatures (740 degrees C) are demonstrated. A high crystalline quality epitaxial material on a c-plane sapphire substrate is attained as corroborated by a combination of x-ray diffraction, high-resolution scanning transmission electron microscopy, and spectroscopic ellipsometry measurements. The hot-wall MOCVD process is transferred to homoepitaxy, and single-crystalline homoepitaxial beta-Ga2O3 layers are demonstrated with a 201 rocking curve width of 118 arc sec, which is comparable to those of the edge-defined film-fed grown (201) beta-Ga2O3 substrates, indicative of similar dislocation densities for epilayers and substrates. Hence, hot-wall MOCVD is proposed as a prospective growth method to be further explored for the fabrication of beta-Ga2O3.
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| 5. |
- Martinsson, Olof, et al.
(författare)
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Age and character of late-Svecokarelian monzonitic intrusions in northeastern Norrbotten, northern Sweden
- 2018
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Ingår i: SGU Rapporter och meddelanden. - Uppsala : Sveriges geologiska undersökning. - 0349-2176. ; 141, s. 381-400
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Tidskriftsartikel (refereegranskat)abstract
- Palaeoproterozoic magmatism in northern Norrbotten shows a complex evolution, with several different plutonic suites ranging in age 1.93–1.70 Ga. Here we present data for three monzonitic intrusions from different parts of the area. They are petrographically and chemically similar, consisting mainly of perthite, augite and orthopyroxene, with megacrysts of poikilitic biotite as a characteristic minor component, and with high Sr and Ba. The intrusions have been dated at 1.80 Ga and may be part of a more extensive magmatic event in northern Sweden, including other chemically similar monzonitic and gabbroic intrusions, which often occur as ring dykes at the Merasjärvi gravity high (MGH) in northeastern Norrbotten. The monzonitic intrusions have A-type signatures and chemical characteristics overlapping those of rocks in arc and within-plate settings. These intrusions may thus have formed in either a back arc setting related to eastward subduction associated with the Transscandinavian Igneous Belt further west (TIB 1), or through a separate igneous event caused by a mantle plume.
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| 6. |
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| 8. |
- Michaëlsson, Karl, 1959-, et al.
(författare)
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Hormone replacement therapy and hip fracture risk : population based case-control study
- 1998
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Ingår i: BMJ - British Medical Journal. - 1756-1833. ; 316:7148, s. 1858-63
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To determine the relative risk of hip fracture associated with postmenopausal hormone replacement therapy including the effect of duration and recency of treatment, the addition of progestins, route of administration, and dose. DESIGN: Population based case-control study. Setting: Six counties in Sweden. SUBJECTS: 1327 women aged 50-81 years with hip fracture and 3262 randomly selected controls. MAIN OUTCOME MEASURE: Use of hormone replacement therapy. RESULTS: Compared with women who had never used hormone replacement therapy, current users had an odds ratio of 0.35 (95 % confidence interval 0.24 to 0.53) for hip fracture and former users had an odds ratio of 0.76 (0.57 to 1.01). For every year of therapy, the overall risk decreased by 6% (3% to 9%): 4% (1% to 8%) for regimens without progestin and 11% (6% to 16%) for those with progestin. Last use between one and five years previously, with a duration of use more than five years, was associated with an odds ratio of 0.27 (0.08 to 0.94). After five years without hormone replacement therapy the protective effect was substantially diminished (-7% to 48%). With current use, an initiation of therapy nine or more years after the menopause gave equally strong reduction in risk for hip fracture as an earlier start. Oestrogen treatment with skin patches gave similar risk estimates as oral regimens. CONCLUSIONS: Recent use of hormone replacement therapy is required for optimum fracture protection, but therapy can be started several years after the menopause. The protective effect increases with duration of use, and an oestrogen-sparing effect is achieved when progestins are included in the regimen.
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| 9. |
- Moberg, Christina, et al.
(författare)
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De unga gör helt rätt när de stämmer staten
- 2022
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Ingår i: Aftonbladet. - 1103-9000.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- 1 620 forskare och lärare i forskarvärlden: Vi ställer oss bakom Auroras klimatkrav
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| 10. |
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