Process for growing HgCdTe base and contact layer in one operation

A method for fabricating a two-layer epitaxial structure by a liquid phase epitaxy (LPE) process, the structure being comprised of a Group II-VI semiconductor material, comprising the steps of:

• providing an LPE growth chamber that contains a molten Group II-VI semiconductor material, the molten Group II-VI semiconductor material having a first temperature;
• growing, at the first temperature, a base layer from the molten Group II-VI semiconductor material, the base layer being grown to have a first bandgap energy;
• isolating the base layer from the molten Group II-VI semiconductor material without removing the base layer from the growth chamber;
• reducing the first temperature of the molten Group II-VI semiconductor material to a second temperature;
• and growing at the second temperature, from the same molten Group II-VI semiconductor material as was used to grow the base layer, a contact layer upon a surface of the base layer to form a two-layer epitaxial structure, the contact layer being grown to have a second bandgap energy that is narrower than the first bandgap energy.

A method for fabricating a two-layer epitaxial structure by a liquid phase epitaxy (LPE) process, the structure being comprised of a Group II-VI semiconductor material, comprising the steps of:

• providing an LPE growth chamber that contains a molten Group II-VI semiconductor material that is comprised of Hg.sub.1-x Cd.sub.x Te,, the molten Group II-VI semiconductor material having a first temperature within a range of approximately 400.degree. C. to approximately 500.degree. C.;
• growing, at the first temperature, a base layer from the molten Group II-VI semiconductor material, the base layer being grown to have a first bandgap energy;
• isolating the base layer from the molten Group II-VI semiconductor material by activating a shutter means to isolate the surface of the base layer from the molten Group II-VI semiconductor material, without removing the base layer from the growth chamber;
• reducing the first temperature of the molten Group II-VI semiconductor material to a second temperature within a range of approximately 250.degree. C. to approximately 350.degree. C. while exposing the surface of the base layer to Hg vapor within the growth chamber and while maintaining a temperature of the base layer to be approximately equal to the temperature of the molten Group II-VI semiconductor material;
• and
• growing at the second temperature, from the same molten Group II-VI semiconductor material as was used to grow the base layer, a contact layer upon a surface of the base layer to form a two-layer epitaxial structure, the contact layer being grown to have a second bandgap energy that is narrower than the first bandgap energy.