Damage-free laser patterning of silicon nitride on textured crystalline silicon using an amorphous silicon etch mask for Ni/Cu plated silicon solar cells

Abstract

We investigate the optimization of laser ablation with a femtosecond laser for direct and indirect removal of SiN x on alkaline textured c-Si. Our proposed resist-free indirect removal process uses an a-Si:H etch mask and is demonstrated to have a drastically improved surface quality of the laser processed areas when compared to our direct removal process. Scanning electron microscope images of ablated sites show the existence of substantial surface defects for the standard direct removal process, and the reduction of those defects with our proposed process. Opening of SiN x and SiO x passivating layers with laser ablation is a promising alternative to the standard screen print and fire process for making contact to Si solar cells. The potential for small contacts from laser openings of dielectrics coupled with the selective deposition of metal from light induced plating allows for high-aspect-ratio metal contacts for front grid metallization. The minimization of defects generated in this process would serve to enhance the performance of the device and provides the motivation for our work.Published by Elsevier B.V.

Review—Silicon Nitride and Silicon Nitride-Rich Thin Film Technologies: Trends in Deposition Techniques and Related Applications

“…In this respect, Tables II and III present details of very recent vapor phase deposition techniques of SiN x thin films, along with a synopsis of intended applications. 15,16,[20][21][22][23][24][25][31][32][33][34][36][37][38] More specifically, Table II summarizes PVD and CVD work, while Table III focuses exclusively on atomic layer deposition ALD.…”

“…35 And much like the case of the hard coatings and computer chip industries, SiN x and SiC y thin films are applied as passivation layers in silicon solar cells. 36,37 Other applications include the use of Si-rich SiN x as host matrix for Si nanocrystals and Si nanoscale inclusions (Si-ni) light emitters for solar cell applications. 31,38 Likewise, SiN x is witnessing extensive use in biotechnology and medical fields, especially in medical devices due to its high chemical stability, enhanced wear endurance, improved fracture toughness, and, unlike its carbide analog, elevated thermal shock resistance, and good biocompatibility.…”

Light absorption enhancement in ultrathin film solar cell with embedded dielectric nanowires

“…Such a layer is then annealed in vacuum at a temperature of 1000 °C for crystallization as shown in Fig. 8b [21][22][23][24][25][26] . Figure 8c shows the deposition of the second silicon layer with a thickness of 236 nm on p-type silicon and Si 3 N 4 layer at a temperature of 690 °C.…”

“…A deposition time of 15 min and temperature of 825 °C are needed to obtain a silicon nitride film of 75 nm thickness 20 . Then, a thin layer of silicon is deposited with a thickness of 100 nm at 1000 °C using dichlorosilane (DCS) or Silane (SiH 4 ) and diborane (B 2 H 6 ) to obtain a heavily doped p-type silicon layer with doping concentration 5 × 10 17 cm −3 21 , 22 . Such a layer is then annealed in vacuum at a temperature of 1000 °C for crystallization as shown in Fig.…”

Silicon Nitride and Hydrogenated Silicon Nitride Thin Films: A Review of Fabrication Methods and Applications

“…The standard method for opening SiNx passivating films is screen printing [ 3 ]. However, Bailly et al [ 4 ] reported laser ablation as a promising alternative method of opening SiNx layers on alkaline-textured crystalline Si to make contact with Si solar cells. This indirect method allows for the mitigation of surface defects, thus enhancing the performance of the device.…”