Infrared laser-based monitoring of the silane dissociation during deposition of silicon thin films

Abstract

The silane dissociation efficiency, or depletion fraction, is an important plasma parameter by means of which the film growth rate and the amorphous-to-microcrystalline silicon transition regime can be monitored in situ. In this letter we implement a homebuilt quantum cascade laser-based absorption spectrometer to measure the silane dissociation efficiency in an industrial plasma-enhanced chemical vapor deposition system. This infrared laser-based diagnostic technique is compact, sensitive, and nonintrusive. Its resolution is good enough to resolve Doppler-broadened rotovibrational absorption lines of silane. The latter feature various absorption strengths, thereby enabling depletion measurements over a wide range of process conditions.

The silane depletion fraction as an indicator for the amorphous/crystalline silicon interface passivation quality

“…2,11 Here, an infrared laser-based plasma diagnostic tool is used in order to measure in situ the silane ͑SiH 4 ͒ depletion fraction during deposition. 12 Silane depletion measurements have provided useful insights such as the origin of higher deposition rates when using very high frequency ͑VHF͒, 13 the determination of the transition region between a-Si:H and c-Si: H depositions, 14 and the optimization of reactor configurations for fast equilibration at ignition. 15 In this paper, the authors study the influence of the silane depletion on a-Si:H layers used for c-Si wafer passivation.…”

“…The silane density is deduced from light absorption spectroscopic measurements ͑the absorption is proportional to the density of the absorbing molecules͒. The monochromatic infrared light of a quantum cascade laser 12,19 is focused and injected through the reactor itself, and the light intensity is measured on the other side. Measurements through the pumped reactor, through the reactor filled with silane at working pressure before ignition, and through the reactor during the steady-state discharge allow us to deduce the silane depletion D.…”

Использование Солнечных Элементов С Двусторонней Контактной Сеткой В Условиях Казахстана

“…Улучшения в технологиях изготовления солнечных элементов и модулей, произошедшие за последние несколько лет, позволили не только значительно по-высить их эффективность и снизить себестоимость, но также расширить спектр их применения и придать им новые функциональные характеристики [1][2][3][4]. Одним из таких улучшений может выступить создание солнечных элементов и модулей, позволяющих генерировать элек-троэнергию при освещении как с фронтальной, так и с тыльной сторон [5].…”

High‐rate deposition of microcrystalline silicon in a large‐area PECVD reactor and integration in tandem solar cells

“…At present, we can turn our efforts to the exploration of a wide range of plasma parameters for the optimization of the high-rate deposition of mc-Si:H i-layers. In situ plasma monitoring based on the diagnostic setup recently developed at the Institute of Microtechnology in Neuchâtel [43] will be used to improve the understanding of the deposition process under study.…”