Patent ID: 8455372

Claim:
A method for cleaning and passivating gallium arsenide (GaAs) surface autologous oxide and depositing Al 2 O 3 dielectric, characterized in that it is comprised of the following steps: (1) after regular chemical cleaning, immediately put the GaAs sample into the prepared sulfur passivation solution which is made of 1-5 g of thioacetamide, 1-4 ml of absolute ethyl alcohol and 1-4 ml of ammonia water, the temperature of passivation reaction is 25 C-60 C, and the passivation time is 5-30 minutes; (2) after passivation, rinse the GaAs sample for 10-60 seconds with deionized water, then purge the sample for 5-15 seconds with high-purity nitrogen, and then immediately put it into the atomic layer deposition (ALD) reaction chamber; (3) before developing the alumina film dielectric, conduct trimethyl aluminum (TMA) pretreatment of the GaAs sample first, and the pretreatment conditions are: introduce the TMA gas to the ALD reaction chamber for 2-8 minutes, and purge for 10-60 seconds with the nitrogen; (4) develop a required high-quality Al 2 O 3 film dielectric by the ALD method, the reaction sources are TMA and deionized water respectively, the temperature of the deposition reaction is 250-350 C, the pressure in the reaction chamber is smaller than 15 torr, and the thickness of the oxide film is adjusted through control of the cycles of the atomic layer reaction.