Formation of ultra-shallow semiconductor junction using microwave annealing

摘要

The present invention is a method of utilizing microwave energy for annealing of ion implanted wafers. By controlling the time, power density and temperature regime, it is possible to substantially fully anneal the wafer while limiting (and substantially preventing) the diffusion of dopant into the silicon, thereby producing higher performance scaled semiconductor devices. It is also possible, using different conditions, to allow and control the dopant profile (diffusion) into the silicon. Another aspect of the present invention is a method of forming a PN junction in a semiconductor wafer having a profile depth less than about 50 nm and a profile wherein the net doping concentration at said PN junction changes by greater than about one order of magnitude over 6 nm wherein the surface concentration of said dopant is greater than about 110²⁰/cm³. The method includes providing a semiconductor wafer which can be single crystal or amorphous surface; implanting into said surface a dopant; exposing the surface to an energy source; the energy source being applied to supply energy at a rate such that the surface is substantially fully annealed before the dopant diffuses greater than about 50 nm. Another aspect of the present invention is having a PN junction formed between a first material of a first conductivity type and a second material of a second conductivity type, the junction has a depth of less than about 50 nm, in the first material the net doping concentration at the junction changes by greater than about one order of magnitude over 10 nm, the maximum value of said first conducting material of said wafer has a surface concentration of greater than about 110²⁰/cm³.