摘要:

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 102–1013atoms/cm2and can cause counterdoping if the boron is distributed by an anneal into a lightly dopedn‐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 SiO2layer will reduce or eliminate boron from the silicon surface.

ISSN:0734-2101    

DOI:10.1116/1.577206

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

The distribution and transport of particles in materials processing plasmas has been studied with a rastered laser light scattering technique. Contrary to expectation, the distribution of particles in a plasma processing tool is rarely random. Instead, structured clouds of particles form at the plasma/sheath boundary. The effect is attributed to trapping of the particles by weak electric field nonuniformities and the characteristic negative charge of isolated particles in a plasma. Field nonuniformities appear to be influenced by the topography and material design of the tool. For example, the presence of a Si wafer often induces significant particle trapping. Examples of particle trapping in a laboratory system are given, and similar phenomena are also verified in a manufacturing sputter deposition tool operating in a class 100 cleanroom. The implications of particle trapping in plasma processing are discussed.

ISSN:0734-2101    

DOI:10.1116/1.577207

出版商:American Vacuum Society    

年代:1991

数据来源: AIP

摘要:

Two models are presented to describe the immediate environment surrounding negatively charged contaminants in an idealized argon plasma. The first model uses Poisson’s equation to determine the contaminant charge and voltage. This model predicts a critical radius of the order of the Debye length below which Poisson’s equation is no longer valid. Below the critical radius and for contaminant radii much less than the Debye length, the Coulomb potential is used to find the contaminant charge and voltage. Both models predict negative charges on the order of 10−14C, and voltages on the same order of magnitude as the electron energy.

ISSN:0734-2101    

DOI:10.1116/1.577208

出版商:American Vacuum Society    

年代:1991

数据来源: AIP