Diffusion length and lifetime of charge carriers are crucial characteristics of crystalline silicon solar cell and their diagnostics (Bullis and Huff, 1995; Guirgis et al., 2009; Pavelka et al., 2007b; Schofthaler and Brendel, 1995; Sinton and Cuevas, 1996; Trupke et al., 2011). Therefore, standardized test methods of lifetime are applied also to specify polysilicon quality […]
Category: Advances in Photovoltaics:. Volume
Regarding its energy consumption, granulated silicon could be a promising solar feedstock (Hamilton and Rami, 2010). However, downstream processes react sensitively toward quality anomalies in silicon granules. Consequently, specific bulk analytical methods must be also applied to granule feedstock (Table 7.8; SEMI E46, n. d.).
Dopant and carbon impurities
Beside dust and metallic impurities, dopants and carbon affect strongly the efficiency of silicon solar cells (Ceccaroli and Lohne, 2006). The substitutional carbon contamination can be determined in polysilicon samples (Hwang et al., 1991) and the resistivity of multicrystalline silicon can also be evaluated (Gosh et al., 1982; Seager, 1985; Tyagi and Sen, 1983). However, […]
Metallic impurities in and on polysilicon
Metallic impurities, particularly metallic impurities interacting with crystal defects detrimentally limit the lifetime of charge carriers in silicon solar cells (Breitenstein et al., 2010; Bronsveld et al., 2010; Buonassisi et al., 2005; Ceccaroli and Lohne, 2006; Hashim et al., 2007; Kwapil et al., 2009; Seibt et al., 2009b; Seifert et al., 2009). For metallic contamination, […]
Particulate contamination on polysilicon feedstock
Analyses of weakly adhered surface contamination and bulk impurities can be applied to polysilicon without phase transition. Testing for particles and dust is particularly important for polysilicon granules (CroBmann and Derzmann, 2006; Ginafranco, 2002; Hashim et al., 2007; Kenji et al., 2005).
Instrumental analytical methods for polysilicon feedstock
Dimensional, morphological, electrical, and chemical data characterize SG-Si feedstock. Direct measurements and analyses can be applied to as – grown polysilicon, indirect measurements, and analysis require monocrystalline or dissolved specimens (Table 7.8) Evaluation technique Characteristics Measurement or analytical Method Analytes, features Reference Direct measurement on as-grown polysilicon Morphology Multifunctional image processing Chunks, granulates Surface properties […]
Online process control of the gas phase
Due to the presence of hydrogen chloride, chlorosilanes, metallic and nonmetallic chlorides, the atmosphere is corrosive in the silane-route processes. Corrosion and precise analytical control are controversial conditions of process control. Controlling the gaseous components of polysilicon subprocesses by process gas chromatography (PGC; Sanji and Toshiyuki, 1988; Tadashi and Tatsuya, 1995; Tellenbach, 2010; Vorotyntsev et […]
ANALYTICAL METHODS OF POLYSILICON AND THEIR STANDARDIZATION
In Section 5.1, we listed relevant properties of polysilicon which affect the performance of solar PV applications and HVM cell processing. SEMI PV17 provides a specification for four different categories of polysilicon feedstock with a list of standardized or generally practiced analytical methods (SEMI PV17-0611, n. d.). The performance of solar cells is limited by […]