Light Enhanced Hydrofluoric Acid Passivation: A Sensitive Technique for Detecting Bulk Silicon Defects

Area of Science:

• Materials Science
• Semiconductor Physics

Background:

• Accurate measurement of bulk lifetime in silicon wafers is crucial for understanding semiconductor material quality.
• Surface recombination can significantly affect bulk lifetime measurements, necessitating effective surface passivation techniques.

Purpose of the Study:

• To present a novel procedure for measuring the bulk lifetime of silicon wafers.
• To achieve a high level of temporary surface passivation using hydrofluoric acid (HF).
• To enable accurate determination of bulk silicon defect characteristics.

Main Methods:

• Chemically cleaning and etching silicon wafers in tetramethylammonium hydroxide.
• Immersing wafers in a hydrofluoric acid (HF) and hydrochloric acid mixture for passivation.
• Utilizing photoconductance (PC) measurements with a halogen lamp illumination (0.2 suns for 1 min) to assess bulk lifetime.

Main Results:

• The procedure successfully measures bulk lifetime exceeding 100 microseconds.
• Accurate determination of bulk silicon defect characteristics is achieved.
• The method is anticipated to be effective for low-concentration bulk silicon defects (<10(12) cm(-3)) with sensitive RT surface passivation.

Conclusions:

• The presented procedure offers a reliable method for measuring silicon wafer bulk lifetime.
• Effective temporary surface passivation in HF is key to accurate bulk defect characterization.
• This technique is vital for advancing the analysis of semiconductor materials.