Passivation of textured crystalline silicon surfaces by catalytic CVD silicon nitride films and catalytic phosphorus doping

Abstract

Silicon nitride (SiNx) films formed by catalytic chemical vapor deposition (Cat-CVD) and phosphorus (P)-doped layers formed by catalytic impurity doping (Cat-doping) are applied for the passivation of pyramid-shaped textured crystalline Si (c-Si) surfaces formed by anisotropic etching in alkaline solution. Lower surface recombination velocities (SRVs) tend to be obtained when smaller pyramids are formed on c-Si surfaces. P Cat-doping is effective for reducing the SRV of textured c-Si surfaces as in the case of flat c-Si surfaces. We realize SRVs of textured c-Si surfaces of ∼8.0 and ∼6.7 cm/s for only SiNx passivation and for the combination of SiNx and P Cat-doping, respectively. These structures also have high optical transparency and low Auger recombination loss, and are of great worth in application for the surface passivation of interdigitated back-contact c-Si solar cells.

Review—Silicon Nitride and Silicon Nitride-Rich Thin Film Technologies: State-of-the-Art Processing Technologies, Properties, and Applications

“…26 • Antireflection coating and passivation layers in Si solar cells. 5,41,49 • Protection/encapsulation layers, sacrificial layers, diffusion barriers, and functional structures, including top encapsulation layers in IC devices and three-dimensional (3D) devices. 22 • Protection/encapsulation layers and spacers in DRAM.…”

“…44 • Passivation and dielectric layers in interdigitated back-contact (IBC) Si solar cells. 49 Table II…”

Phosphorus Catalytic Doping on Intrinsic Silicon Thin Films for the Application in Silicon Heterojunction Solar Cells

“…Doping gases, such as phosphine (PH 3 ) and diborane (B 2 H 6 ), are catalytically decomposed at the hot surface of the filaments into phosphorous (P) and boron (B) radicals. , The radicals move from the filament surface to the sample surface and then diffuse into the silicon material films, forming a shallow depth doping layer with a thickness of 5–20 nm. − Therefore, it is possible to replace the deposition of the doped silicon layer by Cat-doping on the intrinsic layer, which reduces the parasitic absorption of doped silicon layers. Former studies have shown that the material properties, such as conductivity and doping concentration, can be further tuned beyond the level that is achievable for as-grown films. ,, It has also been reported that the passivation quality of SHJ structures could be improved with Cat-doping on different interfaces, such as at the c-Si, a-Si:H­(i), and doped silicon layer surfaces in a SHJ structure. ,,,− …”

Phosphorous Catalytic‐Doping of Silicon Alloys for the Use in Silicon Heterojunction Solar Cells

“…Cat-doping can also improve the passivation quality of the passivated samples with symmetric structures of μc-Si:H(n)/a-Si:H(i)/c-Si/a-Si:H(i)/ μc-Si:H(n) and a-Si:H(n)/a-Si:H(i)/c-Si/a-Si:H(i)/a-Si:H(n) in which the interfaces of μc-Si:H(n) and c-Si are cat-doped, respectively. [10,[14][15][16] In this work, we investigate the phosphorus cat-doping on μc-Si:H(n), nc-SiO x :H(n), and μc-SiC:H(n) for the use in SHJ solar cells. The phosphorus distribution profiles of three silicon alloy films after cat-doping process were obtained by secondary ion mass spectrometry (SIMS).The impact of cat-doping on electrical property of silicon alloy films was evaluated from conductivity measurement.…”

“…Cat‐doping can also improve the passivation quality of the passivated samples with symmetric structures of μc‐Si:H(n)/a‐Si:H(i)/c‐Si/a‐Si:H(i)/μc‐Si:H(n) and a‐Si:H(n)/a‐Si:H(i)/c‐Si/a‐Si:H(i)/a‐Si:H(n) in which the interfaces of μc‐Si:H(n) and c‐Si are cat‐doped, respectively. [ 10,14–16 ]…”