The Technique On GaAs Microtips Growed By Liquid Phase Epitaxy And Its Peeling

Scanning near-field optical microscopy (SNOM) is a novel photoelectrical tool for the research on material’s structure, morphology, chemistry and physical properties. It uses the evanescent field confined at the tiny aperture to provide images of rough surfaces with a resolution which is beyond the classical optical diffraction limit down to nanometer scale. One of its most potential applications is in ultrahigh density optical data storage. Therefore, a compact structure and miniaturization of the SNOM sensor has been proposed which can be industrialized production by semiconductor industry. And the SNOM sensor is composed of a pyramidal microtip, a vertical-cavity surface-emitting laser (VCSEL) cavity and a PIN detector. Among them, the quality of the pyramidal microtip which is utilized to read and white the optoelectronic information is essential to the whole system. Hence, it is a key issue to fabricate high quality pyramidal microtips for the SNOM sensor for now.This paper mainly introduces the process on the selective liquid phase epitaxy (LPE) technique, which includes including the treating of the substrate, SiO2mask preparation, photolithography, wet etching, liquid phase epitaxial growth and so on. However there is invariably a residual growth solution spot on one side of the GaAs microtip using the conventional selective LPE technique. The quality and performance of the microtip is seriously affected by the defect which is caused by the horizontal sliding graphite boat based on the experiment data. We propose a new technique, rotation dumping method, for separating growth solution from wafer. In this technique, the wafer would be rotated from upside to downside in the rotatable graphite boat when the film deposition is done. And the growth solution will drop automatically owing to the gravity. Experimental results indicate that the residual solution spots on the sidewalls of the pyramidal microtips produced by the novel method become very small, and even disappear. And this technique promotes the application of the SNOM sensor. What’s more, a technique on peelable GaAs microtips is also introduced. With these two techniques combined, it’s beneficial to the integration of the SNOM sensor.