The semiconductor industry has been red-hot over the last few years, and it isn't just Nvidia and Advanced Micro Devices delivering substantial gains for investors. The digital economy is forever expanding, and more products and services require advanced chip hardware, which is creating pockets of opportunity for a number of companies.Axcelis Technologies (ACLS -2.39%) is one of them. Shares of the semiconductor service company have rocketed higher by more than 440% over the last five years, even after acco ...