The preparation of high quality polycrystalline Si films at low temperature using PECVD.

The subject of this research is the preparation of highly crystallized polycrystalline Si films at low temperature using a plasma-enhanced chemical vapor deposition(PECVD)system，by utilizing effects of etching on the growing surface of films and those of a change in the surface morphology of substrates.In the present work，we investigated the changes in the crystalline qualily as follows：Effects of SiF I D24文件D2 addition to a SiH文件D 24文件D 2 feed gas.(2)Effects of H I D 22个D 2 addition in addition to SiF I D 24个D 2 in(1)，(3)effects of a change in deposition temperature.And(4)effects of plasma-pretreatment on substrates prior to the deposition of Si films under fixed conditions。As a result，(1)the SiF I D24文件D2 addition enhances the crystallization of films deposited at a low temperature，but high flow-rate conditions of SiF I D 24文件D2 caused an increase in the density of O atoms incorporated in the Si films deposition。(2)The addition of H I D 22 I D 2 in addition to SiF I D 24 I D 2 under low temperature conditions further enhanced the crystallinity，but decreased the size of crystal grains.Furthermore，the H I D22 ii D2 addition acted to suppress the incorporation of O atoms after deposition as stated in the above item(1)。(3)The crystal quality of Si films strongly depended on the deposition temperature，Td：Under conditions of Td&lt；150℃and Td*650℃，the crystallization of the Si films was suppressed and the film structure was amorphous.(4)When Si films were deposited on substrates subjected to pretreatment of plasma using CF I D 24文件D2，N I D 22文件D2，and/or H I D 22文件D2，the crystallinity of the Si films was enhanced。Such enhanced crystallinity was connected with preparation of substrates with a proper degree of surface roughness。Thus，the addition of SiF D 24个D 2 and H D 22个D 2 to a SiH D 24个D 2 feed gas and the plasma pretreatment of substrates are useful technologies for fabricating highly crystallized polycrystalline Si films at low temperature.

The subject of this research is the preparation of highly crystallized polycrystalline Si films at low temperature using a plasma-enhanced chemical vapor deposition (PECVD) system, by utilizing effects of etching on the growing surface of films and those of a change in the surface morphology of substrates. In the present work, we investigated the changes in the crystalline qualily as follows : Effects of SiFィイD24ィエD2 addition to a SiHィイD24ィエD2 feed gas. (2) Effects of HィイD22ィエD2 addition in addition to SiFィイD24ィエD2 in (1), (3) effects of a change in deposition temperature. And (4) effects of plasma-pretreatment on substrates prior to the deposition of Si films under fixed conditions. As a result, (1) the SiFィイD24ィエD2 addition enhances the crystallization of films deposited at a low temperature, but high flow-rate conditions of SiFィイD24ィエD2 caused an increase in the density of O atoms incorporated in the Si films after deposition. (2) The addition of HィイD22ィエD2 in addition to SiFィイD24ィエD2 under low temperature conditions further enhanced the crystallinity, but decreased the size of crystal grains. Furthermore, the HィイD22ィエD2 addition acted to suppress the incorporation of O atoms after deposition as stated in the above item (1). (3) The crystal quality of Si films strongly depended on the deposition temperature, Td : Under conditions of Td < 150 ℃ and Td * 650 ℃, the crystallization of the Si films was suppressed and the film structure was amorphous. (4) When Si films were deposited on substrates subjected to pretreatment of plasma using CFィイD24ィエD2, NィイD22ィエD2, and/or HィイD22ィエD2, the crystallinity of the Si films was enhanced. Such enhanced crystallinity was connected with preparation of substrates with a proper degree of surface roughness. Thus, the addition of SiFィイD24ィエD2 and HィイD22ィエD2 to a SiHィイD24ィエD2 feed gas and the plasma pretreatment of substrates are useful technologies for fabricating highly crystallized polycrystalline Si films at low temperature.