SAN FRANCISCO — Shares of chipmakers Micron and SanDisk surged on Thursday after a solid-state drive maker warned of component shortages, increasing expectations that production cutbacks have stopped a slump in prices for flash memory chips. Shares of Boise, Idaho-based Micron jumped 5.97 percent to $6.55 while Milpitas-based SanDisk surged 8.0 percent to $43.85. Late on Wednesday, San Jose-based OCZ Technology Group Inc said it expected revenue for the second quarter to fall below its previous forecast because of a shortage of the NAND chips it uses to build storage devices. Wall Street saw the revised outlook as fresh evidence that lower output by NAND manufacturers is reducing supply and stabilizing low prices.