Silicon-based dielectric stack passivation of Si-epitaxial thin-film solar cells

A solar cell, comprising:

• a metallurgical-grade Si (MG-Si) substrate;
• a first heavily doped crystalline-Si layer situated above the MG-Si substrate;
• a lightly doped crystalline-Si layer situated above the first heavily doped crystalline-Si layer;
• a second heavily doped crystalline-Si layer situated above the lightly doped crystalline-Si layer;
• front electrodes situated above the second heavily doped crystalline-Si layer;
• a passivation layer situated between the second heavily doped crystalline-Si layer and the front electrodes, wherein the passivation layer passivates a surface of the second heavily doped crystalline-Si layer, wherein the passivation layer includes a three-layer dielectric stack, wherein the three-layer dielectric stack includes a SiOxNy layer in contact with the second heavily doped crystalline-Si layer, a hydrogenated SiNx layer in contact with the front electrodes, and a oxide layer situated between the SiOxNy layer and the hydrogenated SiNx layer, and wherein the SiOxNy layer relaxes interfacial stress between the second heavily doped crystalline-Si layer and the oxide layer;
• and
• a backside ohmic-contact layer situated on the backside of the MG-Si substrate.