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A novel ion beam-induced cleaving process for slicing c-Si wafers ranging in thickness from 20IJm to 150IJm with near zero kerf-loss and markedly low overall cost has been developed and demonstrated to be capable of large-area thin PV substrate manufacturing. This paper introduces this new wafering technology, called the Direct Film Transfer (OFT) process, and describes its practical utilization to produce wafers spanning from ultra thin foils to free-standing substitute wafers in high-volume silicon PV cell manufacturing. In addition to the 50IJm thick wafering capability, recent 20IJm and 150IJm wafering results complete the extension and applicability of the DFT process. The material characteristics and preliminary solar cell efficiencies of the DFT wafers are presented. With the advent of this new wafering technology, development work and production use of ultra thin CZ silicon based solar cells are expected to accelerate.

Advances in layer-transfer methods are making large-area growth templates a reality for GaN and GaAs compound semiconductors. QMAT will introduce its layer-transfer technology tuned for microLED applications integrating functional layers that simplify printability and testability.MicroLED yield and test challenges will also be discussed.

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Achieving and maintaining high yield during microLED display production requires integration of in-process EL functional test into the mass-transfer assembly process flow. Known Good Die (KGD) data from EL emission efficiency and color test of the source carrier substrate is key to directing mass-transfer assembly of functionally good and matched microLED devices. Mass-transfer approaches have varying compatibility with inprocess functional test data that can limit yield and throughput. This paper will analyze the issues and challenges of current microLED mass-transfer technologies in production and compatibility with in-process test. An optimized process flow utilizing KGD in-process test and compatible mass-transfer assembly methods is proposed.