Russell J. Low

High efficiency selective emitter enabled through patterned ion implantation

Selective emitter cell architectures offer the opportunity of improved cell efficiency over standard cell architectures through improved blue response, reduced saturation current and lower contact resistance. However, few selective emitter cell concepts have been successfully adopted into high volume manufacturing, often due to the associated increase in process complexity and cost. This paper demonstrates that patterned ion implantation provides a roadmap to lower PV module and system

Benefits of Zero Degree Single Wafer High Energy Implants for Advanced Semiconductor Device Fabrication

/Wp costs through improved cell efficiency and reduced manufacturing cost. Ion implanted cell efficiency improvements, which can be up to +1% absolute, are a result of not only the selective emitter cell architecture, but also improved emitter quality, oxide passivation and increased light collection area through the elimination of laser edge isolation. Manufacturing cost reductions result from reduced processing steps and improved process uniformity and cell binning.

Indium Performance on the V810

High energy well implants for retrograde well formation are usually tilted to avoid channeling. However, this can cause the well profile under the STI (Shallow Trench Isolation) to be skewed or asymmetric due to shadowing by the resist. This results in poor inter‐well isolation and increased leakage currents. This problem becomes more pronounced below 65 nm design rules. In this paper, using experimental data and TCAD simulations we demonstrate the improvement in inter‐well isolation and junction characteristics that can be achieved with true‐zero well implants. Finally, we briefly discuss the corresponding die shrinkage that can be expected.

High efficiency selective emitter cells using patterned ion implantation

Indium has been used as an alternative p‐type dopant to boron in a number of implant applications. Typically, solids such as InCl3 have been used as source feed materials, which have proven problematic for a number of reasons. Issues have included charge life, conditioning & PM recovery time (e.g. where hydroscopic materials have been used). This paper presents productivity improvements made to the V810 for running indium ion beams, along with advances made in process control.