The Use of Metalorganics in the Preparation of Semiconductor Materials: VI . Formation of IV–VI Lead and Tin Salts

Abstract

The ever-increasing interest in the use of IV-VI compounds, particularly PbTe and Pbl-~SnxTe, for IR detectors and the success demonstrated in the use of metalorganics in preparing III-V and II-VI compounds and alloys (1) prompted a study to extend the metalorganic chemical vapor deposition (CVD) technique to the preparation of IV-VI compounds also. Growth studies were performed on PbTe and on single-crystal insulating substrates transparent in the visible part of the spectrum. The transparent substrates were used in order to help in determining the onset of crystal growth as evidenced by a darkening of the substrate and to facilitate optical studies and microprobe analyses of the crystals formed. These substrates included mechanically polished A1203, MgA1204, and BaF2, and freshly cleaved (in air) MgO, NaC1, CaF2, and BaF2, BaF2 was the primary insulator used in these investigations since in thin wafer form it is transparent to 11-1'2 #m radiation, is more stable than NaC1 at temperatures ,~625~ and matches the thermal expansion of the IV-VI's relatively closely (2).The metalorganic compounds used in this study, some of their pertinent properties, and the suppliers are listed in Table I.The Pb, Sn, and Te compounds were used as received in stainless steel bubblers except for purging with tI2 carrier gas prior to use in film growth experiments. The bubblers were maintained at room temperatuze during film growth. Pd-purified It2 at a total flow of about 10 liters/min was used as the carrier gas in the deposition experiments. HeS and H2Se were at a minimum purity of 99.5 and 98.0%, respectively (Matheson Gas Products, East Rutherford, New Jersey).BaF2 and CaF2 were purchased from the Harshaw Chemical Company (Solon, Ohio). Rockwell polished single-crystal BaF2 windows and BaF2 and CaF2 wafers cleaved from 1 in. diameter rods were used as substrates. Cleaving into (lll)-oriented substrate blanks was performed just prior to use in a film growth experiment. The a-A1203 was Czochralski material from Union Carbide Corporation (San Diego, California) and polished by Insaco (Quakertown, Pennsylvania). The MgA1204 was produced and polished by Union Carbide Corporation. The NaC1 and MgO were single crystals that were cleaved just before use.The PbTe substrates were all wafers sawed from crystals obtained from Electronic Materials Corpora-* Electrochemical Society Active Member.

Growth and characterization of tin disulfide (SnS2) thin film deposited by successive ionic layer adsorption and reaction (SILAR) technique

“…Present day technologists are busy using these materials in designing opto-electronic devices, a part of solar collectors, etc. Thin films of tin sulfides have been grown by spray pyrolysis [6], chemical bath [7], and chemical vapour deposition either from organometallic precursors [8]. Single crystals of SnS 2 have been grown by the vapor phase [9].…”

The Preparation and Properties of Tin Oxide Films Formed by Oxidation of Tetramethyltin

“…These properties are shared with only a few other materials, and many techniques for its deposition have therefore been developed. In this paper, a new technique is described for the chemical vapor deposition of SnO2 films based on the oxidation of tetramethyltin (TMT) at relatively low temperatures (450~176 The growth of electronic materials using organometallic compounds as sources was pioneered by Manasevit and co-workers, who have used TMT to obtain films of SnTe, SnS, and PbSnTe chalcogenide glasses (8). Substrafe temperatures ranging from 500 ~ to 750~ are necessary in the SnC14 process.…”

Tribenzyltin(IV)chloride Thiosemicarbazones: Novel Single Source Precursors for Growth of SnS Thin Films

“…[12,13] Methods such as electroless deposition, [14] spray-pyrolysis, [15] low pressure [16] and plasma-assisted [17] CVD, chemical bath deposition, [18] vapor transport methods, [19] melt growth, [20] 4 ], where M is a Group IV element. [23] Thermogravimetric analysis and mass spectrometry data showed that [Sn(SR) 4 ] results in RS-SR in the gas phase, supporting the formation of disulfide during the CVD process.…”