(Reuters) -The world's largest technology companies are tapping debt markets, raising almost $100 billion through recent bond offerings, as they seek to bolster their artificial intelligence infrastructure. This marks a shift for Silicon Valley firms that typically relied on cash to fund their investments. Tech giants, including Amazon, Microsoft, Google, Oracle, and Meta, are set to nearly double last year's investment by spending$400 billion on data centers despite mounting fears of an AI bubble. Alph ...