Method to incorporate, and a device having, oxide enhancement dopants using gas immersion laser doping (GILD) for selectively growing an oxide layer

摘要

A method for forming a uniform and reliable oxide layer on the surface of a semiconductor substrate using projection gas immersion laser doping (P-GILD) is provided. A semiconductor substrate is immersed in an oxide enhancing compound containing atmosphere. The oxide enhancing compound containing atmosphere may include phosphorus, arsenic, boron or an equivalent. A 308 nm excimer laser is then applied to a portion of the substrate to induce incorporation of the oxide enhancing compound into a portion of the substrate. The deposition depth is dependent upon the strength of the laser energy directed at the surface of the substrate. A uniform and reliable oxide layer is then formed on the surface of the substrate by heating the substrate. The laser may be applied with a reflective reticle or mask formed on the substrate. An E. sup.2 PROM memory cell having a program junction region in a silicon substrate is also provided. An oxide layer is positioned between a program junction and a floating gate. The oxide layer is formed by a single or multiple thermal oxidation step(s) to have at least a first oxide thickness due to a GILD oxide enhancing compound underlying a region of the oxide having at least the first oxide thickness.