Lam Research is buying KLA-Tencor Corp. for about $10.6 billion, creating a huge player in the semiconductor sector that will rival Applied Materials Inc. The combined company, to be called Lam Research Corp., will have a market capitalization of around $19 billion, about equal to that of Applied Materials, and says it will serve 42 percent of the wafer fabrication equipment market when the deal closes in the middle of next year. The offer, for $67.02 per share, marks a 24 percent premium to the closing price for KLA-Tencor Corp. on Tuesday.