Lucent Technologies Inc.

At&t Bell Laboratories

David James Eaglesham

Hans-Joachim Ludwig Gossmann

John Milo Poate

Peter Adriaan Stolk

Konstantin K Bourdelle

A process for semiconductor device fabrication in which a Czochralski silicon substrate is implanted with boron is disclosed. The boron is implanted using an energy of about 500 keV to about 3 MeV and a dose of about 3.times.10.sup.13 /cm.sup.2 to about 3.times.10.sup.14 /cm.sup.2. In order to reduce the threading dislocation density in the substrate to less than about 10.sup.3 /cm.sup.2 at a depth in the substrate of at least about 0.5 .mu.m, after the implant, the substrate is annealed in a two-step process. First the substrate is annealed at a temperature in the range of about 725.degree. C. to about 775.degree. C. followed by an anneal at a temperature of at least about 900.degree. C. The duration of the first step is selected to provide a dislocation density of less than about 10.sup.3 /cm.sup.2 at the desired depth in the substrate.

Process for device fabrication using a high-energy boron implant

Diffusion of ion-implanted dopant is controlled by incorporating electrically inactive impurity in a semiconductor layer by at least one crystal growth technique.

Process for controlling dopant diffusion in a semiconductor layer

Process for controlling dopant diffusion in a semiconductor layer and

Disclosed is a method of making a semiconductor device that comprises MBE at substrate temperatures substantially lower than conventionally used temperatures. A significant aspect of the method is the ability to produce highly doped (e.g., 10.sup.19 cm.sup.-3) epitaxial single crystal Si layers. The deposition can be carried out such that substantially all (at least 90%) dopant atoms are electrically active at 20.degree. C. However, the method is not limited to Si MBE. Exemplarily, the method can be used to produce epitaxial single crystal GaAs having very short (e.g., &lt;100ps) carrier lifetime. Such material can be useful for, e.g., high speed photodetectors. Incorporation into the method of a relatively low temperature rapid thermal anneal makes possible low temperature MBE growth of relatively thick semiconductor layers.

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David James Eaglesham