Motorola Corporation

Other

Richard B Gregory

Syd R Wilson

Charles J Varker

Orin W Holland

Thomas Allen Wetteroth

Darrell Keith Thomas

Systems and methods are described for transfer of a thin-film via implantation, wafer bonding, and separation. A method for transfer of a thin-film, includes: implanting a source crystal with ions along a crystallographic channel and at a temperature of at least approximately 200&deg; C. to i) form a strained region and ii) define the thin-film; then bonding a surface of the thin-film to a target wafer; and then separating a) the target wafer and the thin-film from b) a remainder of the source crystal along the strained region. The systems and methods provide advantages because the electrical carriers in the crystal, and consequently the thin-film, are not deactivated and the quality of the transferred thin-film is improved.

Method for transfer of thin-film of silicon carbide via implantation and wafer bonding

Implantation of oxygen or nitrogen in polysilicon layers to a dose above about 10.sup.15 ions/cm.sup.2 retards rapid grain boundary migration of conventional dopants such as B, P, As, Sb, and the like during dopant activation. Pre-annealing of the poly films to increase the grain size also decreases rapid grain boundary migration. The effects can be combined by first pre-annealing and then implanting oxygen or nitrogen before introducing the dopant. It is desirable to anneal the oxygen implant before introducing the dopant to allow for oxygen diffusion to the grain surfaces where it precipitates and blocks the grain boundaries. Vertical and lateral migration of the dopants can be inhibited by placing the implanted oxygen or nitrogen between the dopant and the location desired to be kept comparatively free of dopants. When very high dopant activation temperatures are used the blocking effect of the oxygen on the grain boundaries is overwhelmed by dopant diffusion through the grains.

Means for stabilizing polycrystalline semiconductor layers

Hillock formation as a result of heating uncapped polycrystalline silicon layers can be avoided by first implanting the uncapped poly layers with silicon, oxygen, or nitrogen prior to heating. Equivalent mono-atomic oxygen or nitrogen doses in the range of about 10.sup.15 to about 5.times.10.sup.16 ions/cm.sup.2 at energies in the range 10-50 keV are useful with good results being obtained with equivalent oxygen doses of 2.times.10.sup.15 ions/cm.sup.2 at 30 keV. When polysilicon layers with this oxygen implant are heated to about 1150 degrees C., a temperature which would ordinarily produce pronounced hillock formation in un-capped, un-treated poly layers, it is found that hillock formation is suppressed. The implanted oxygen concentrations are far below what is required to produce a separate oxide layer or phase. Some effect on poly layer sheet resistance is observed for implanted oxygen but the implanted layers have sheet resistances within a factor of two of those without the oxygen implants.

Method of preventing hillock formation in polysilicon layer by oxygen

Implantation of oxygen or nitrogen in polysilicon layers to a dose above about 10.sup.15 ions/cm.sup.2 retards rapid grain boundary migration of conventional dopants such as B, P, As, Sb, and the like during dopant activation. Pre-annealing of the poly films to increase the grain size also decreases rapid grain boundary migration. The efffects can be combined by first pre-annealing and then implanting oxygen or nitrogen before introducing the dopant. It is desirable to anneal the oxygen implant before introducing the dopant to allow for oxygen diffusion to the grain surfaces where is precipitates and blocks the grain boundaries. Vertical and lateral migration of the dopants can be inhibited by placing the implanted oxygen or nitrogen between the dopant and the location desired to be kept comparatively free of dopants. When very high dopant activation temperatures are used the blocking effect of the oxygen on the grain boundaries is overwhelmed by dopant diffusion through the grains.

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Phoenix, AZ, United States of America

Richard B Gregory