TY - JOUR

T1 - Detachment yield statistics for kerfless wafering using the porous silicon process

AU - Gemmel, C.

AU - Hensen, J.

AU - Kajari-Schröder, S.

AU - Brendel, Rolf

N1 - Funding Information: The authors thank the Federal Ministry of Economic Affairs and Energy (BMWi) and the State of Lower Saxony for funding this work, Jessica Strey for the sample preparation and Sascha Wolter for the fruitful discussion.

PY - 2019/11

Y1 - 2019/11

N2 - The porous silicon (PSI) process is a wafering method to fabricate high quality kerfless crystalline Si wafers by epitaxial wafer growth on porous Si and subsequent detachment from a reusable substrate wafer. The process yield is a key parameter for the economic viability of the PSI process. We experimentally demonstrate the detachment of 59 out of 62 PSI wafers with a size of 10 × 10 cm2, and separation layer etch current densities of 105–120 mA/cm2 for electrochemically etching the porous Si, and for substrate wafers with a resistivity of 15.7–16.9 mΩcm. We discuss the statistics of how to deduce a detachment probability from this. From our experiments, we determine a detachment yield of at least 88% with an error probability of 5%. The demonstration of a 99% detachment yield with an error probability of 5% would require at least 300 successfully detached wafers with no failed detachment. Samples have a minority carrier density ranging from 1 to 1.7 ms before any external gettering, which demonstrates the high electric quality of the PSI wafers.

AB - The porous silicon (PSI) process is a wafering method to fabricate high quality kerfless crystalline Si wafers by epitaxial wafer growth on porous Si and subsequent detachment from a reusable substrate wafer. The process yield is a key parameter for the economic viability of the PSI process. We experimentally demonstrate the detachment of 59 out of 62 PSI wafers with a size of 10 × 10 cm2, and separation layer etch current densities of 105–120 mA/cm2 for electrochemically etching the porous Si, and for substrate wafers with a resistivity of 15.7–16.9 mΩcm. We discuss the statistics of how to deduce a detachment probability from this. From our experiments, we determine a detachment yield of at least 88% with an error probability of 5%. The demonstration of a 99% detachment yield with an error probability of 5% would require at least 300 successfully detached wafers with no failed detachment. Samples have a minority carrier density ranging from 1 to 1.7 ms before any external gettering, which demonstrates the high electric quality of the PSI wafers.

KW - Detachment probability

KW - Porous silicon process

KW - Statistical evaluation

KW - Yield

UR - http://www.scopus.com/inward/record.url?scp=85070581356&partnerID=8YFLogxK

U2 - 10.1016/j.solmat.2019.110061

DO - 10.1016/j.solmat.2019.110061

M3 - Article

AN - SCOPUS:85070581356

VL - 202

JO - Solar Energy Materials and Solar Cells

JF - Solar Energy Materials and Solar Cells

SN - 0927-0248

M1 - 110061

ER -