Ohmic Contact to n-GaN Using RT-Sputtered GaN:O

Area of Science:

• Materials Science
• Semiconductor Physics

Background:

• Ohmic contacts to n-type gallium nitride (GaN) are crucial for GaN-based devices.
• High resistivity and technological challenges limit current ohmic contact solutions.

Purpose of the Study:

• To develop a novel and effective method for intentional oxygen doping of sputtered GaN films.
• To create highly conductive n+-GaN:O films for improved ohmic contacts.

Main Methods:

• Room temperature magnetron sputtering of an oxygen-doped single crystal GaN target.
• Characterization of the resulting n+-GaN:O films' structure, surface, and electron concentration.

Main Results:

• Successfully produced n+-GaN:O films with a polycrystalline structure and crack-free surface.
• Achieved a high free electron concentration of 7.4 × 10^18 cm^-3.
• Demonstrated ohmic contact to GaN:Si with a specific contact resistance of ~10^-5 Ωcm^2 using the n+-GaN:O sub-contact layer after thermal treatment.

Conclusions:

• Intentional oxygen doping via sputtering is an effective method for creating highly conductive n+-GaN films.
• The developed method offers a promising pathway for a new class of low-resistance ohmic contacts for n-GaN.
• These findings have significant implications for advancing GaN-based electronic device technology.