A method for producing a solar cell including the steps of forming a p-type microcrystalline silicon oxide layer on a glass substrate using a PECVD method and raw gases comprising Silane gas, Diborane gas, Hydrogen gas and Carbon Dioxide gas. The method may employ a frequency of between about 13.56-60 MHz. The PECVD method may be performed at a power density of between about 10-40 mW/cm2 and a pressure of between about 0.5-2 Torr, and with a ratio of Carbon Dioxide to Silane of between about 0.10-0.24; a ratio of Diborane to Silane of 0.10 or less, and a ratio of Silane to Hydrogen of 0.01 or less. A tandem solar cell structure may be formed by forming top and bottom layers by the method described above, and placing the top layer over the bottom layer.