Boron contamination has been detected by secondary ion mass spectrometry at almost every surface and interface in silicon microelectronics structures. Areal densities for boron are typically 102–1013 atoms/cm2 and can cause counterdoping if the boron is distributed by an anneal into a lightly doped n-type region. Boron was quantified by encapsulating the surface of the layer of interest with an identical layer and thereby retaining matrix homogeneity across the interface where the original surface is located. The origin of boron was shown to be airborne contamination. Boron in the atmosphere and the borosilicate glass in the high efficiency particulate air filters used in clean room construction have been identified as contamination sources. Accumulation of boron on a polysilicon surface follows a relationship similar to that for oxide growth. Processing with hydrogen, buffered HF cleaning of the surface, or growth of a removable SiO2 layer will reduce or eliminate boron from the silicon surface.

A series of bulk proton-exchanged lithium niobate waveguides has been prepared by using concentrated sulfuric acid as the proton source and varying the time and temperature of the exchange process. The optical and physical properties of the proton-exchanged lithium niobate layer have been measured and found to be essentially identical to proton-exchanged layers obtained by other workers using the benzoic acid process. Sulfuric acid offers a number of advantages over benzoic acid as a proton source, including a wider temperature liquid range and a greater ease of handling in a clean-room environment.

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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-