Apparatus and methods for reducing minority carriers in a memory array are described herein. Minority carriers diffuse between ON cells and OFF cells, causing disturbances during write operation as well as reducing the retention lifetime of the cells. Minority Carrier Lifetime Killer (MCLK) region architectures are described for vertical thyristor memory arrays with insulation trenches. These MCLK regions encourage recombination of minority carriers. In particular, MCLK regions formed by conductors embedded along the cathode line of a thyristor array, as well as dopant MCLK regions are described, as well as methods for manufacturing thyristor memory cells with MCLK regions.