Growth of 4‑Inch InP Single-Crystal Wafer Using the VGF-VB Technique.

Area of Science:

• Materials Science
• Crystal Growth
• Semiconductor Technology

Background:

• High-quality Indium phosphide (InP) single crystals are crucial for advanced electronic and optoelectronic devices.
• Existing Vertical Gradient Freeze (VGF) and Vertical Bridgman (VB) methods face challenges in producing large-diameter (>4-in.) InP crystals with uniform doping.

Purpose of the Study:

• To develop and validate a combined VGF-VB crystal growth technique for producing large-diameter, uniformly doped InP single crystals.
• To address the limitations of conventional VGF and VB methods in achieving controlled doping concentrations in large InP crystals.

Main Methods:

• A hybrid VGF-VB method was employed, utilizing a pyrolytic boron nitride (PBN) crucible within a vacuum-sealed quartz tube.
• The process involved initial crystal seeding and melting using the VGF method, followed by cylindrical growth using the VB method.
• The growth was performed in a nominally 4.5-in. VGF-VB InP single-crystal furnace to yield 4-in. wafers.

Main Results:

• The VGF-VB technique successfully produced nominally 4.5-in. InP single crystals.
• The resulting crystals exhibited a low maximum etch pit density (EPD) of ≤ 300 cm^-2 at the tail end.
• Electrical parameter uniformity was significantly improved to within ± 6%.

Conclusions:

• The combined VGF-VB crystal growth technique is a reliable and effective method for producing high-quality, large-diameter InP single crystals.
• This hybrid approach overcomes the doping uniformity challenges associated with conventional methods.
• The results confirm the suitability of the VGF-VB technique for manufacturing InP crystals for demanding semiconductor applications.