Composite piezoelectric substrate and preparation method thereof

Abstract

The invention provides a composite piezoelectric substrate and a preparation method thereof. The method comprises the following step: alternately and circularly introducing a first reaction atmosphereand a second reaction atmosphere into a reaction furnace until the target composite piezoelectric substrate is prepared, wherein the target composite piezoelectric substrate comprises a first substrate layer and a second substrate layer which are arranged in the silicon wafer, are sequentially formed inwards from the outer surface of the silicon wafer and are alternately stacked; and the oxidizing temperature in the reaction furnace is 850-1200 DEG C when the oxygen-containing atmosphere is introduced into the reaction furnace, and the nitriding temperature in the reaction furnace is 1100-1400 DEG C when the nitrogen-containing atmosphere is introduced into the reaction furnace. In the preparation process, dozens to hundreds of silicon wafers can be placed in the reaction furnace, that is, dozens to hundreds of composite piezoelectric substrates can be prepared in each reaction furnace each time; and in the preparation process, only oxygen-containing atmosphere and nitrogen-containingatmosphere need to be alternately introduced into the reaction furnace, and the silicon wafers do not need to be moved, so that the production efficiency is greatly improved.

Description

technical field [0001] The application belongs to the field of semiconductor element preparation, in particular to a composite piezoelectric substrate and a preparation method thereof. Background technique [0002] The surface acoustic filter is a special filtering device made by using the piezoelectric effect of piezoelectric materials and the physical characteristics of surface acoustic wave propagation. The surface acoustic filter generally includes a composite piezoelectric substrate based on the basic structure design of the Bragg reflector, and a piezoelectric thin film layer laminated on the composite piezoelectric substrate, wherein the composite piezoelectric substrate generally includes alternately stacked first A substrate layer and a second substrate layer, the first substrate layer and the second substrate layer have different acoustic impedances, the piezoelectric thin film layer is used to transmit the acoustic wave signal, and the composite piezoelectric subs...

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Problems solved by technology

[0005] In order to solve the problem in the prior art that when the composite piezoelectric substrate is prepared by the deposition method, it is necessary to frequently switch the deposition chamber, which affects the production efficiency

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