High-power rapid microwave annealing of Si

Summary form only given. Expanding the $300 billion/year Si electronics industry requires the fabrication of Si nano-devices that are smaller, faster, and cheaper than those currently used in today´s microprocessors. Reducing device size and increasing switch speeds requires high concentrations of dopant atoms into thin regions (/spl sim/15 nm) of Si through low-energy, high-dose ion implantation. This process not only damages the Si, but also leaves the dopants deposited in interstitial (i.e., inactive) sites. A high temperature thermal anneal repairs the implant damage (i.e., reform the crystal lattice) and moves the implanted dopants into Si lattice sites, where they are electrically active. Unfortunately, this high-temperature anneal degrades sensitive portions of the device and drives dopant diffusion. Dopant diffusion dilutes the concentration of the dopants, thereby diminishing their impact, and intermixes the source/drain and channel regions of the device. The intermixing of these regions diminishes the electrical isolation needed for proper device operation. Because high temperatures are needed to repair the implant damage and activate the dopants, a classic engineering tradeoff occurs, which limits the ultimate size reduction of Si devices. We have developed an ultra-rapid, pulsed, gyrotron anneal technique capable of heating Si to 1300/spl deg/C in only a few milliseconds. The gyrotron operates at 110 GHz for pulse durations of 2-10 milliseconds. The power density and pulse duration control the heating rate and the peak temperature achieved. Because only the top several microns of Si receives substantial heating, the sample cools through conduction of heat from the surface into the bulk, resulting in a cooling rate that exceeds 4,000,000/spl deg/C/sec. The high anneal temperatures provide extraordinary electrical activation and thorough repair of the implant damage. Limiting the time spent above 800/spl deg/C minimizes device degradation and diffusion o- dopants.