Comprehensive study of rapid, low-cost silicon surface passivation technologies

Silicon nitride processing for control of optical and electronic properties of silicon solar cells

“…The LFSiN-passivated wafer received a forming gas anneal (500°C, 15 min) prior to the measurements. 4 This figure illustrates that even for the same index of refraction, the effectiveness of the passivation depends on the deposition method. The higher S eff at higher injection level for the low-frequencydeposited films is attributed to the ion bombardment received during the deposition, creating a different type of defect at the Si/SiN interface.…”

“…This process gives low S eff of less than 2 cm/s at the intrinsic FZ-Si/PECVDSiO 2 interface. 4 Therefore, PECVD oxide passivation is considered promising for improving the efficiency and cost effectiveness of Si solar cells.…”

“…Recently, it has been determined that SiN coatings deposited by plasma-enhanced chemical vapor deposition (PECVD) can accomplish the following functions: (1) act as an excellent AR coating whose refractive index can be controlled by controlling the deposition conditions, (2) serve as a buffer through which a contact metallization can be fired to make reliable ohmic contacts, (3) produce a passivation layer to reduce the surface recombination of the device, and (4) allow diffusion of H into the device to passivate defects and impurities for improved device performance. [4][5][6][7] An integration of these multiple functions demands a detailed knowledge of various mechanisms that influence optical parameters, interface charge, and transport of H in Si. This paper reviews optical properties of SiN and its design as an optimum AR film, the role of SiN as a metallization buffer, process considerations for retention and subsequent diffusion of H to produce impurity defect passivation, and considerations for surface passivation by the nitride coating.…”

Hydrogenation of Si from SiNx(H) films: Characterization of H introduced into the Si

“…10 The modest H concentration introduced by a postdeposition anneal of a SiN x film is consistent with the sensitivity of the effectiveness of hydrogenation treatments to processing methods. [5][6][7][8][9] That is, one is not in the situation where there is an excess of H available to effectively passivate all of the defects that might be present. Therefore, changes in the H concentration that result from differences in processing methods can have a pronounced effect.…”

Impact of firing on surface passivation of p-Si by SiO2/Al and SiO2/SiNx/Al stacks

“…Many alternatives based on low-temperature processes therefore receive currently strong research interest, including plasma-enhanced chemical vapor deposition (PECVD) 3 , rapid thermal oxidation 4 and electrochemical oxidation 5 . The rear contact of a passivated emitter and rear cell (PERC) or PERL-type cell is typically achieved by local laser ablation of the dielectric stack, followed by deposition of an Al film, which is then co-fired in a belt furnace together with screen printed front contacts.…”