LPCVD has the longest track record, as most of the early adopters of TOPCon kick-started their mass production with LPCVD. In LPCVD, the tunneling silicon oxide layer is grown in situ thermally, which is known for its quality over the deposited layers. However, LPCVD typically had a few shortcomings, such as wraparound, low life of the quartzware, and external doping of polysilicon. However, the technology has made significant progress in all these areas.

LAPLACE, the leading equipment maker in this field, has made multiple enhancements to its LPCVD platform. Top of the list is a double-loading configuration. In order to have some control over the wraparound, LPCVD tools are typically loaded with one wafer per slot. Then, irrespective of the deposition method, the post-deposition chemical treatment is inevitable. However, companies like LAPLACE have developed a process that enables wafers to be placed back-to-back within the same tube, doubling throughput while controlling the wraparound. This feature is retrofittable to existing single-loading tools, eliminating the need for new hardware, emphasizes LAPLACE (see Poly Thickness & Edge Passivation For TOPCon Cells).

The company also increased wafer capacity per tube from 2,400(GEN4) to 2,880 (GEN5), and reported that 88.5 GW of installed capacity now runs on this configuration. Additionally, with the help of specific recipes and special know-how, LAPLACE says it has been able to improve the lifespan of the quartz. The company applies a coating to the quartz tube that extends its lifespan from 4 months up to 12 months while doubling the lifespan of quartz boats to 6 months.

The text is an edited excerpt from TaiyangNews’ latest Market Survey on Solar Cell Production Equipment 2025, which can be downloaded for free here.