You could use an FPGA, although I don't know what your cost requirements are. It probably will be much easier to do it in hardware than to actually get an FPGA if you know precisely what you want and don't plan on many changes. A good old NE555 has a rise and fall time of ~100ns and is routinely used for microsecond level timing, plus they cost like $0.50 whereas even a very cheap FPGA is about $20 for the chip itslef, plus they are't as builder-friendly unless you have access to some nice equipment (like a PCB printer). So unless you want to buy an FPGA board pre-made I would recommend a 555-based timing circuit.
