Simultaneous Analysis of Boron and Phosphorus in Deposited Glasses by Inductively Coupled Plasma Atomic Emission Spectroscopy with Internal Standardization

Abstract

ConclusionsWe have examined the photoluminescent properties of thin films of ZnS:Mn as a function of deposition temperature and method of manganese doping. We find that the method of doping, implantation or cosputtering, is not important but the deposition temperature is. Films grown at 463 K exhibit bright yellow luminescence from the Mn 2+ ion with minimal annealing, but films deposited at 503 K require substantial annealing before yellow emission is observed. This is linked to changes in the undoped films~ as characterized by the appearance of an intense green emission in the 77 K PL spectra. We have discussed the result speculatively in terms of energy transfer from the excited Mn 2 § ion to a red emitting defect. Irrespective of the fine details, the technological implications for thin film photoluminescent devices are clear; the most effective deposition temperature for electroluminescence is below 473 K, but failing this, substantial annealing is required to bring out the manganese emissions.We have recently reported the use of ion chromatography (IC) and electron microprobe (EMP) analysis of boron and phosphorus in deposited glass films used in VLSI manufacture (1). Levy and Kometani (2), and Wcissman (3) have reported the use of inductively coupled plasma atomic emission spectroscopy (ICP-AES) for the analysis of deposited glass films. We report here on the use of a simultaneous ICP-AES instrument with internal standardization. The polychromator used in the simultaneous instrument uses relatively broad windows centered on the analytical lines, and is thus less sensitive to small changes in frequency response. In the internal standard mode of analysis the response of the analytical emission lines is ratioed to the response of a standard line during calibration and analysis. This helps to eliminate much of the variation in response caused by drift in the plasma and the optics. The simultaneous ICP-AES analysis is also more rapid, since all emission lines are measured at the same time.Two types of deposited glass were measured in this work. Borophosphosilicate glass (BPSG), produced by low temperature chemical vapor deposition from a mixture of silane, phosphine, diborane and oxygen (4), and borophosphotetraethylorthosilicate glass (BPTEOS), pro~ duced using tetraethylorthosilane as the silicon source (5). ExperimentalAll chemicals not otherwise specified were ACS analytical reagent grade and were used as received. Potassium hydrogen phosphate was primary standard grade (Fisher Scientific) and was dried at 110~ overnight before use. Deionized water (DIW) was prepared using a Milli-Q system (Millipore Corporation) to a resistivity of 18 M~-cm. ICP-AES measurements were made using an Instruments SA JY-48 based on a 1 meter Ebert monochromator. A stand-