PULSED AND CW LASER TREATMENTS OF IMPLANTED POLYSILICON SOLAR CELLS

Conventional ion implantation and unanalyzed ion bombardment have been used to elaborate the rectifying N+ contact of polycrystalline silicon (Wacker, HEM, CGE) solar cells. Two surface laser annealing in the liquid phase (Nd : YAG laser) and in the solid phase (CO2 laser) regimes have been used. The properties of the solar cells so processed have been investigated. For both doping procedures and both annealing techniques, the cells (conversion) efficiencies under AM1 illumination exceeded 11% for the various polysilicon substrates

PULSED AND CW LASER TREATMENTS OF IMPLANTED POLYSILICON SOLAR CELLS

Les contacts redresseurs N+ de photopiles au silicium polycristallin (Wacker, HEM, CGE) ont été réalisés soit par implantation conventionnelle du dopant (P+) soit par "incrustation" d'ions (implantation sans séparation magnétique PF5). Deux techniques de recuit de surface par faisceau laser en phase liquide (laser Nd : YAG) et en phase solide (laser Co2) ont été employées. Les performances des photopiles ainsi élaborées ont été étudiées. Pour les deux types de dopage et de recuit, le rendement de conversion photovoltaïque des cellules dépasse 11% AM1 pour les matériaux polycristallins utilisés.Conventional ion implantation and unanalyzed ion bombardment have been used to elaborate the rectifying N+ contact of polycrystalline silicon (Wacker, HEM, CGE) solar cells. Two surface laser annealing in the liquid phase (Nd : YAG laser) and in the solid phase (CO2 laser) regimes have been used. The properties of the solar cells so processed have been investigated. For both doping procedures and both annealing techniques, the cells (conversion) efficiencies under AM1 illumination exceeded 11% for the various polysilicon substrates

Optimal duration of preoperative therapy in unilateral and nonmetastatic Wilms' tumor in children older than 6 months: results of the Ninth International Society of Pediatric Oncology Wilms' Tumor Trial and Study

To determine the optimal duration of preoperative chemotherapy to further increase the proportion of stage I tumors by comparison of two regimens in the treatment of patients older than 6 months who have unilateral Wilms' tumor. Eligible patients (n = 382) initially received four weekly doses of vincristine (VCR) and two courses of actinomycin D (AMD) and were randomized either to be operated on (4-week group [n = 193]) or to receive 4 more weeks of the same chemotherapy regimen (8-week group [n = 189]). The assessment criterion was the observed percentage of stage I tumors. After surgery, patients were assigned according to tumor stage and histology to four different treatment groups: stage I and favorable histology (n = 5) were to have no further treatment (NFT); stage I and standard histology or anaplasia (n = 244), VCR and AMD for 17 weeks (AV); stages II and III and favorable or standard histology, VCR, AMD, and an anthracycline for 27 weeks (AVE) with no abdominal radiotherapy for stage II N0 disease (n = 75) or with a 15-Gy dose of abdominal irradiation (RTH) in case of stages IIN1 and III (n = 56). Anaplastic tumors staged higher than I or clear-cell sarcoma of the kidney (14), AMD, VCR, an anthracycline, and ifosfamide for 36 weeks (DEVI). No advantage was found in favor of prolonged preoperative treatment. The percentages obtained for the 4-week and the 8-week groups, respectively, were as follows: stage I, 64% versus 62%; intraoperative tumor rupture rate, 1% versus 3%; 2-year EFS, 84% versus 83%; and 5-year OS, 92% versus 87%. Two-year EFS and 5-year OS rates, respectively, of the different treatment groups were as follows: NFT, 100% for both EFS and OS; AV, 88% and 93%; AVE, 84% and 88%; AVE RTH, 71% and 85%; and DEVI, 71% and 71%. The rate of abdominal recurrences in stage II N0 nonirradiated patients was 6.6%. The 4-week schedule pre-nephrectomy chemotherapy regimen should be considered the standard treatment. Clinical trials should continue to improve the cure rate of high-risk patients and the quality of life of children with a more favorable prognosi

Results of the Sixth International Society of Pediatric Oncology Wilms' Tumor Trial and Study: a risk-adapted therapeutic approach in Wilms' tumor

The Sixth International Society of Pediatric Oncology study (SIOP6) concerned Wilms' tumor with favorable histology, preoperatively treated to obtain a high rate of stage I patients, and sought to reduce treatment for patients with stage I and stage II negative nodes (IIN0) tumors and to find better therapy to prevent relapses in stage II positive nodes (IIN1) and stage III patients. Eligible patients (N = 509) had received four weekly doses of vincristine (VCR) and two courses of dactinomycin (AMD) preoperatively and were assigned after surgery, according to stage and lymph node involvement, to three different prognostic groups, which were to be randomized. Stage I patients (n = 303) received VCR and AMD either for 17 weeks (S) or 38 weeks (L). Stage IIN0 patients (n = 123) received either 20 Gy irradiation (R+) or no irradiation (R-) and received VCR and AMD for 38 weeks. Stage IIN1 and III patients (n = 83) received intensified VCR and AMD (INTVCR) versus VCR, AMD, and Adriamycin (ADRIA; Doxorubicin Farmitalia Carbo Erba, Rueil, Malmaison, France; doxorubicin). Assessment criteria were 2-year disease-free survival (DFS) and 5-year survival (SURV) percentages. A stopping rule was added that took into account abdominal recurrences for the stage IIN0 trial. A 52% rate of stage I tumors was obtained, with a low rate of ruptures (7%). The 2-year DFS and 5-year SURV rates according to the different therapeutic groups were stage I, 92% versus 88% (equivalent) and 95% versus 92% for S and L, respectively; stage IIN0, 72% versus 78% (stage equivalent) and 88% versus 85% for R+ and R-, respectively; and stage IIN1 and stage III, 49% versus 74% (P < .029) and 77% versus 80% for INTVCR and ADRIA, respectively, which results in an 82% DFS and 89% SURV rate for the entire trial population. However, six abdominal metastases observed during the first year of follow-up (FU) in the R- group versus none in the R+ group resulted in discontinuation of the stage IIN0 trial. Risk-adapted therapy to limit risk of sequelae is possible. More intensive chemotherapy is necessary to prevent abdominal recurrences in nonirradiated stage IIN0 patients treated preoperatively. A three-drug protocol is necessary in stage IIN1 and stage III patient