A process for annealing crystal damage in ion implanted semiconductor devices in which the device is rapidly heated to a temperature between 450.degree. and 900.degree. C. and allowed to cool. It has been found that such heating of the device to these relatively low temperatures results in rapid annealing. In one application the device (17) may be heated on a graphite element (14) mounted between electrodes (15) in an inert atmosphere in a chamber (11). The process may be enhanced by the application of optical radiation from a Xenon lamp (19).
When heating a semiconductor wafer by means of application of radiated light, subsidiary heating means which elongates along the circumference of the wafer is employed to additionally heat or to preheat the circumferential portion of the wafer so as to make the temperature of the wafer uniform at the entire surface thereof. Use of such subsidiary heating means is effective to prevent the occurrence of such a damage as slip line or the like in the wafer.
A two step rapid thermal anneal (RTA) has been studied for activating Be implanted GaAs, where a short duration high temperature step is used to electrically activate the Be followed by a longer low temperature anneal for lattice re-growth. PN diodes show a substantial reduction in reverse diode leakage current after the lower temperature second step anneal, when compared to a single step RTA or to furnace annealing (FA). For low energy Be implants, no difference in electrical activation between the single step and the two step anneal is observed. Raman studies demonstrate that residual substrate impurities and high Be concentrations inhibit restoration of single crystal lattice characteristics after RTA. Lattice quality is also shown not to limit diode characteristics in the RTA material.
Ion implanted gallium arsenide substrates are annealed by providing an arsenic-containing gaseous ambient on all sides of the substrate, and heating the gallium arsenide substrate with broad area incoherent light.
A diamond thermistor is described. Surface portions of temperature sensing diamond of the thermistor are doped with impurity ions by ion implantation except for a sensing area thereof. A pair of electrodes are formed on the impurity regions in order to make good ohmic contacts with the diamond. The damage caused by the ion implantation is remedied by subjecting the diamond film to laser annealing.
