摘要:

Potential health hazards in the chemical vapor deposition of tin oxide films from tetramethylin, dimethylin dichloride, and tin tetrachloride have to be balanced against the benefits to solar cell fabrication. Concerns regarding the toxicity, costs, and physical properties of and the quality of the tin oxide films produced with these tin precursors are outlined. (AIP)

ISSN:0094-243X    

DOI:10.1063/1.37122

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

 We describe here a process for the manufacture of solar modules based on II−VI compounds which has several advantages over procedures typical of other thin film solar technologies−specifically amorphous silicon. These advantages arise from the fact that all raw materials and waste products are in solid or liquid form. In this paper we concentrate on the systems and equipment necessary to eliminate uncontrolled discharge of hazardous materials produced during the fabrication of CdS/CdTe/ZnTe solar modules.  (AIP)

ISSN:0094-243X    

DOI:10.1063/1.37138

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

There are two chief issues in the evaluation of liquid sources of arsenic for thin‐film semiconductor deposition: safety and material quality. Safety concerns center upon toxicity by inhalation, and they favor the use of fully substituted arsenic alkyls; e.g., trimethylarsine and triethylarsine. Considerations of material quality, which reduce finally to the minimization of carbon incorporation, favor mono‐ and disubstituted alkyl derivatives of arsine; those currently being evaluated are tertiarybutylarsine, diethylarsine, and dimethylarsine.

ISSN:0094-243X    

DOI:10.1063/1.37121

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Gas source growth of GaAs using arsine offers advantages for large scale fabrication of a range of devices including solar cells. The toxicity of arsine presents substantial problems of safety and liability. This provides a strong incentive to develop alternate gas sources for As. Trimethyl arsenic is a promising candidate that is up to 6500 times less toxic than arsine and is a low vapor pressure liquid that is much easier to contain and neutralize in case of an accident. It has been used in a vacuum MOCVD system to grow GaAs with a background p doping level of 6–8×1016cm−3, a mobility of 276 cm2/Vsec, and room temperature photoluminescence full width, half height of 41 meV. This should be sufficient for the growth of high performance solar cells.

ISSN:0094-243X    

DOI:10.1063/1.37128

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

 In addition to the technical and political problems associated with the safe handling of phosphine, arsine, and other binary hydrides, there are performance drawbacks to the use of these hydrides in wafer processing for semiconductor manufacturing. The metalic arganic organic chemical vapor deposition reagent program at American Cyanamid has explored whether new sources can offer better solutions to existing problems than continued efforts to work with existing materials. Our studies of new phosphorus and arsenic sources are briefly described in this paper.  (AIP)

ISSN:0094-243X    

DOI:10.1063/1.37129

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

From 1980 to 1984, the National Institute for Occupational Safety and Health (NIOSH), along with the U.S. Environmental Protection Agency (EPA), sponsored a study of worker exposures and controls in semiconductor manufacturing. The study was conducted by Battelle Columbus Laboratories and PEDCO Environmental. Walk‐through surveys were conducted at 21 plants and in‐depth studies were done at four of these plants. Processes studied included photolithography, chemical vapor deposition, wet chemical etching and cleaning, plasma etching, diffusion, ion implantation, and metallization. Air samples were collected for acetone, antimony, arsenic, boron, n‐butyl acetate, diborane, 2‐ethoxyethyl acetate, hexamethyldisilizane, hydrogen chloride, hydrogen fluoride, 2‐methoxyethanol, methyl ethyl ketone, nitric acid, phosphorus, sulfuric acid, and xylene. In addition, radio‐frequency and ionizing radiation were monitored and ventilation measured. In general, results were well below recommended standards for routine operations. One exception was radio‐frequency radiation where there was the potential for overexposure in several instances. Worker exposures during maintenance operations and process upset conditions were not able to be evaluated.

ISSN:0094-243X    

DOI:10.1063/1.37130

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

In photovoltaic cell fabrication, organometals (alkyl metals) may be used in such processes as metalorganic chemical vapor deposition, transparent contact oxide deposition, doping, and ion implantation. Although these compounds offer potential performance advantages over earth metals and possibly greater safety in handling than metal hydrides, they are not without risk to health and property. Most organometals can ignite spontaneously in air. Some also react violently with water. Oxidation by‐products from these reactions are hazardous to health. Of the organometals used in photovoltaic cell fabrication, only the toxicology of organotins (triethyl‐, trimethyl‐ and tetramethyltin) was studied extensively. In mammalian systems, tetramethyltin is rapidly dealkylated to trimethyltin. Although tin was classified by some investigators as an essential trace element, the effects of organotin compounds on humans are poorly known. Animal studies show that the most prominent effects of trimethyltin are on the central nervous system. Several observations of poisoning were reported; effects ranged from reversible neurologic disorders to death. Limited available data suggest that humans respond to single acute doses and more alarmingly to repeated sub‐toxic doses, suggesting a cumulative effect. Toxicologic properties of diethyltelluride also were evaluated in animal experiments. The compound had toxic effects on the blood, liver, kidney, heart, and skin. Based on these studies and others of related compounds (e.g., methylmercury, tributyltin) extreme caution should be exercised in using organometal compounds in photovoltaic cell manufacturing.

ISSN:0094-243X    

DOI:10.1063/1.37131

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Semiconductor research facilities have many of the same health and safety hazards as large‐scale manufacturing plants. The novel and episodic nature of laboratory activity requires a different perspective for medical surveillance and biologic monitoring. Basic principles of medical surveillance for laboratory personnel are reviewed and analyzed. Approaches to biologic monitoring and the role of biologic exposure indices are discussed. Specific types of hazards including dopants, gallium arsenide, toxic inhalations, and physical hazards are placed in a framework consistent with laboratory exposures. Reproductive effects and carcinogenic potential of selected substances are assessed along with possible monitoring strategies.

ISSN:0094-243X    

DOI:10.1063/1.37132

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Incidents affecting operational performance within the photovoltaic industry can be reduced by implementing unusual occurrence reporting systems. This paper identifies the major components of such a system, including background and criteria for determining an unusual occurrence, components of an unusual occurrence report form, and the process cycle from an occurrence to its resolution. Examples of occurrences at the Solar Energy Research Institute (SERI) are presented along with their final results.

ISSN:0094-243X    

DOI:10.1063/1.37133

出版商:AIP    

年代:1988

数据来源: AIP

摘要:

Highly toxic hydrogen selenide and hydrogen sulfide gases are used in the production of copper‐indium‐diselenide photovoltaic cells by reactive sputtering. In the event of an accident, these gases may be released to the atmosphere and pose hazards to public and occupational safety and health. This paper outlines an approach for designing systems for the control of these releases given the uncertainty in release conditions and lack of data on the chemical systems involved. Accidental releases of these gases in storage cabinets can be controlled by either a venturi and packed‐bed scrubber and carbon adsorption bed, or containment scrubbing equipment followed by carbon adsorption. These systems can effectively reduce toxic gas emissions to levels needed to protect public health. The costs of these controls (∼$0.012/Wp) are samll in comparison with current (∼$6/Wp) and projected (∼$I/Wp) production costs.

ISSN:0094-243X    

DOI:10.1063/1.37134

出版商:AIP    

年代:1988

数据来源: AIP