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- Grahn, J. V., et al.
(author)
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A low-complexity 62-GHz f(T) SiGe heterojunction bipolar transistor process using differential epitaxy and in situ phosphorus-doped poly-Si emitter at very low thermal budget
- 2000
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In: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 44:3, s. 549-554
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Journal article (peer-reviewed)abstract
- A low-complexity SiGe heterojunction bipolar transistor process based on differential epitaxy and in situ phosphorus doped polysilicon emitter technology is described. Silane-based chemical vapor deposition at reduced pressure was used for low-temperature SiGe epitaxy. Following SiGe epitaxy, the process temperature budget was kept very low with 900 degrees C for 10 s as the highest temperature step. A very high current gain of almost 2000 and cut off frequency of 62 GHz were achieved for a uniform 12% Ge profile. The breakdown voltage BVCEO and forward Early voltage were equal to 2.9 and 6.5 V, respectively.
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| 4. |
- Akram, Frida Hosseini, et al.
(author)
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Incidence of Subclinical Hypothyroidism and Hypothyroidism in Early Pregnancy
- 2017
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In: Journal of Women's Health. - : Mary Ann Liebert Inc. - 1540-9996 .- 1931-843X. ; 26:11, s. 1231-1235
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Journal article (peer-reviewed)abstract
- Background: Untreated and subclinical hypothyroidism (SCH) has been associated with adverse pregnancy complications such as increased risk of miscarriage, hypertension, preeclampsia, and preterm delivery. However, in Sweden, screening for thyroid dysfunction during pregnancy is only recommended for women with a high risk of thyroid disease. Therefore, the aim of this study was to determine the incidence of clinical and SCH in women in the first trimester of pregnancy.Materials and Methods: In this prospective study, 1298 pregnant women were divided into three groups: one unselected general screening group (n=611), one low-risk group comprising women without risk factors for thyroid disorder (n=511), and one high-risk group comprising women with an inheritance or suspicion of thyroid disease or undergoing treatment for thyroid disease (n=88). Serum was obtained up to gestational week 13, and thyrotropin (TSH) was analyzed.Results: The incidences of thyroid dysfunction in the three screening groups were 9.8% in the general screening group, 9.6% in the low-risk group, and 10.2%, p=0.948, in the high-risk group. In the women with known hypothyroidism on levothyroxine treatment, 50.6% had serum TSH levels above 2.0mIU/L.Conclusions: High-risk screening is not useful in predicting which women are at risk of thyroid disease in early pregnancy since approximate to 10% of women with SCH or hypothyroidism could not be diagnosed in this way.
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| 6. |
- Baskar, K., et al.
(author)
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Surface morphology and localised states of GaInNAs single quantum wells grown by MOVPE
- 2003
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In: Journal of Crystal Growth. - 0022-0248 .- 1873-5002. ; 248, s. 431-436
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Journal article (peer-reviewed)abstract
- GaInNAs/GaAs single quantum wells (QWs) have been grown by metalorganic vapour phase epitaxy (MOVPE). The surface morphology has been studied by atomic force microscopy (AFM). The density of pits observed on the surface of QW structures was found to depend on the growth temperature and dimethylhydrazine (DMHy) flow. Cross-sectional AFM image showed the presence of defects at the interface of GaInNAs/GaAs. The low temperature photoluminescence characteristics of the QWs as a function of growth temperature. DMHy flow and density of surface pits have been discussed. The origin of pit formation is addressed based on the pyrolysis products present during the growth of QWs. The results suggest that higher growth temperature maybe desirable to obtain good quality GaInNAs QWS.
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| 7. |
- Bjorkholm, M., et al.
(author)
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Treatment-related risk factors for transformation to acute myeloid leukemia and myelodysplastic syndromes in myeloproliferative neoplasms
- 2011
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In: Journal of Clinical Oncology. - : American Society of Clinical Oncology: JCO. - 0732-183X .- 1527-7755. ; 29:17, s. 2410-2415
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Journal article (peer-reviewed)abstract
- Purpose: Patients with myeloproliferative neoplasms (MPNs), including polycythemia vera, essential thrombocythemia, and primary myelofibrosis, have a propensity to develop acute myeloid leukemia (AML) and myelodysplastic syndromes (MDSs). Using population-based data from Sweden, we assessed the role of MPN treatment and subsequent AML/MDS risk with special focus on the leukemogenic potential of hydroxyurea (HU). Methods: On the basis of a nationwide MPN cohort (N = 11,039), we conducted a nested case-control study, including 162 patients (153 and nine with subsequent AML and MDS diagnosis, respectively) and 242 matched controls. We obtained clinical and MPN treatment data for all patients. Using logistic regression, we calculated odds ratios (ORs) as measures of AML/MDS risk. Results: Forty-one (25%) of 162 patients with MPNs with AML/MDS development were never exposed to alkylating agents, radioactive phosphorous (P32), or HU. Compared with patients with who were not exposed to HU, the ORs for 1 to 499 g, 500 to 999 g, more than 1,000 g of HU were 1.5 (95% CI, 0.6 to 2.4), 1.4 (95% CI, 0.6 to 3.4), and 1.3 (95% CI, 0.5 to 3.3), respectively, for AML/MDS development (not significant). Patients with MPNs who received P32 greater than 1,000 MBq and alkylators greater than 1 g had a 4.6-fold (95% CI, 2.1 to 9.8; P = .002) and 3.4-fold (95% CI, 1.1 to 10.6; P = .015) increased risk of AML/MDS, respectively. Patients receiving two or more cytoreductive treatments had a 2.9-fold (95% CI, 1.4 to 5.9) increased risk of transformation. Conclusion: The risk of AML/MDS development after MPN diagnosis was significantly associated with high exposures of P32 and alkylators but not with HU treatment. Twenty-five percent of patients with MPNs who developed AML/MDS were not exposed to cytotoxic therapy, supporting a major role for nontreatment-related factors. © 2011 by American Society of Clinical Oncology.
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| 8. |
- Bowallius, Olof, et al.
(author)
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Scanning Capacitance Microscopy for Two-Dimensional Doping Profiling in Si- and InP-Based Device Structures
- 1999
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In: Physica Scripta T. - 0281-1847. ; 79, s. 163-166
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Journal article (peer-reviewed)abstract
- We report on the application of cross-sectional Scanning Capacitance Microscopy (SCM) for studying two-dimensional doping variations in Si and InP device structures. Different sample preparation methods were evaluated and the response of the SCM signal from various test structures, including epitaxially grown layers with n- and p-doping concentrations ranging from 5 × 1014 to 2 × 1019 cm-3, were examined under different imaging conditions. The technique was further evaluated by imaging a Si bipolar transistor structure and an InP-based buried heterostructure diode laser. We conclude that valuable information can be gained also from complex device structures.
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| 9. |
- Bowallius, Olof, et al.
(author)
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Scanning capacitance microscopy investigations of buried heterostructure laser structures
- 1999
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In: Applied Surface Science. ; 144-145:0, s. 137-140
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Journal article (peer-reviewed)abstract
- In this work, InP-based buried heterostucture lasers are used to demonstrate the utility of scanning capacitance microscopy (SCM) for characterising complex device structures. The lasers use p-n junctions formed by selective regrowth of p and n doped InP layers around a mesa for current confinement. For comparison, the regrowth was performed by liquid phase epitaxy (LPE) and metal organic vapour phase epitaxy (MOVPE). Our investigations show that scanning capacitance microscopy is capable of detecting the p-n junctions formed at different regions of the device and thereby allows visualisation of the current confinement regions. Variations in the imaged depletion regions are attributed to doping variations due to modification of the regrowth process by the mesa. The SCM data show significant differences between the devices regrown by LPE and MOVPE and the results are consistent with the different regrowth mechanisms. Finally, the implications of the SCM data on device performance are discussed. © 1999 Elsevier Science B.V. All rights reserved.
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| 10. |
- Bowallius, O., et al.
(author)
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Scanning capacitance microscopy investigations of SiC structures
- 2001
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In: Materials Science in Semiconductor Processing. - 1369-8001 .- 1873-4081. ; 4:03-jan, s. 209-211
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Journal article (peer-reviewed)abstract
- We have applied scanning capacitance microscopy (SCM) to investigate SIC structures grown by vapour-phase epitaxy. The SCM technique is evaluated using n- and p-type doping staircase structures with doping concentrations ranging from 10(16) to 10(20) cm(-3). The n- and p-type doping was obtained by doping SiC with nitrogen and aluminium, respectively. The sample cross-sections for SCM were obtained by simple cleaving. For doping levels above 10(17) cm(-3) the SCM data are consistent with doping data obtained independently from secondary ion mass spectroscopy (SIMS). Treating the samples with diluted hydrofluoric acid significantly improves the SCM signal for the low-doped regions. The SCM technique has been used to investigate doping redistribution in patterned regrowth of n- and p-type SIC around dry-etched mesas. In both cases, contrast variations were seen close to the mesa walls, indicative of doping variations; lower and higher incorporation for p- and n-type, respectively. The observations are shown to be consistent with the expected trends in dopant incorporation in the SiC material.
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