Method of making integrated circuit structure with vertical isolation from single crystal substrate comprising isolation layer formed by implantation and annealing of noble gas atoms in substrate

A method of isolating an integrated circuit structure in a single crystal silicon semiconductor wafer from portions of said substrate beneath said integrated circuit structure which comprises:

• a) forming an isolation layer, comprising noble gas atoms selected from the group consisting of non, argon, krypton, and xenon atoms, and enmeshed with semiconductor atoms, in a region beneath a surface of said silicon semiconductor wafer by the steps of:
• i) implanting with said noble gas atoms a region beneath said surface of said silicon wafer by implanting said noble gas atoms through said surface of said wafer:
• 1) at an energy level sufficient to form said isolation layer of noble gas atoms, after subsequent annealing, at a depth of at least about 0.5 microns from the surface of said wafer;
• and
• 2) at a dosage level sufficient to inhibit recrystallization of the silicon semiconductor lattice in the implanted region upon subsequent annealing of said wafer;
• and
• ii) then annealing said silicon semiconductor wafer to recrystallize said semiconductor wafer above said implanted region;
• resulting in the formation of said isolation layer of noble gas atoms enmeshed with semiconductor atoms;
• and
• b) then, without oxidizing said isolation layer, forming an integrated circuit structure in said silicon semiconductor wafer between said surface and said isolation layer.

A method of isolating an integrated circuit structure in a single crystal silicon semiconductor wafer from portions of said wafer beneath said integrated circuit structure which comprises:

• a) forming an isolation layer comprising argon atoms enmeshed with semiconductor atoms in a region beneath the surface of said semiconductor wafer by the steps of:
• i) implanting a region beneath said surface of said wafer with argon atoms at a dosage level of at least about 2.times.10.sup.15 argon atoms/cm.sup.2 and an energy level of at least 1.5 meV through said surface to inhibit recrystallization of the semiconductor lattice in the implanted region upon subsequent annealing of said wafer;
• and
• ii) then annealing said substrate to recrystallize said silicon semiconductor wafer above said implanted region;
• resulting in the formation of said isolation layer of argon atoms enmeshed with semiconductor atoms;
• and
• b) then, without oxidizing said isolation layer, forming an integrated circuit structure in said silicon semiconductor wafer between said surface and said isolation layer.