Silicon carbide-based combined temperature-pressure micro-electro-mechanical system (mems) sensor chip and preparation method thereof

A silicon carbide-based combined temperature-pressure micro-electromechanical system (MEMS) sensor chip, comprising:

• a pressure measuring unit;
• and
• a temperature measuring unit;
• wherein the pressure measuring unit and the temperature measuring unit are integrated on the silicon carbide-based combined temperature-pressure MEMS sensor chip;
• the pressure measuring unit comprises a silicon carbide substrate and an insulating layer arranged on the silicon carbide substrate;
• the insulating layer is provided with a metal ohmic contact circuit;
• a cavity is arranged on a back side of the silicon carbide substrate;
• a front side of the silicon carbide substrate with the cavity is configured as a pressure-sensitive diaphragm;
• a raised island is arranged above the front side of the silicon carbide substrate;
• the raised island is configured as a substrate of the temperature measuring unit;
• four piezoresistive strips are arranged along a circumferential direction of a root of the pressure-sensitive diaphragm, and arranged between the raised island and the pressure-sensitive diaphragm;
• and the four piezoresistive strips are connected through the metal ohmic contact circuit to form a Wheatstone bridge;
• and
• the temperature measuring unit comprises the raised island, a thin-film thermocouple positive electrode and a thin-film thermocouple negative electrode;
• the thin-film thermocouple positive electrode and the thin-film thermocouple negative electrode are arranged on the raised island;
• a head of the thin-film thermocouple positive electrode and a head of the thin-film thermocouple negative electrode are overlapped to form a hot junction;
• an end pin of the thin-film thermocouple positive electrode and an end pin of the thin-film thermocouple negative electrode constitute a cold end;
• and the cold end is connected to an external circuit through a metal lead.