CN203519540U - Single-chip micro-gas sensor - Google Patents

Abstract

A monolithic micro-gas sensor, the heating element and the temperature measuring element of the sensor are fixed on the silicon frame support through the fixed end, a catalyst carrier is arranged on the heating element, the heating element and the temperature measuring element are independent of each other, and there is no electrical connection between the heating element and the temperature measuring element; the heating element is used to heat the catalyst carrier alone, and the temperature measuring element is used to detect the temperature rise caused by the catalytic combustion of gas alone; a gas sensor processed by MEMS technology for detecting gas concentration in coal mines, and its preparation process is compatible with CMOS process. Advantages: The sensor has simple configuration, easy operation, low power consumption and high sensitivity. The heating element is embedded in the catalyst carrier as a whole, which improves the efficiency of electrothermal heating, efficiently utilizes the heat of the heater, and can also independently control the heating element and detect the temperature measuring element.

Description

A single-chip microgas sensor

technical field

The utility model relates to a gas sensor, in particular to a single-chip micro gas sensor.

Background technique

At present, the catalytic combustion gas sensor based on traditional platinum wire heating is still widely used in coal mines, but its power consumption is relatively large, which cannot well meet the application requirements of the Internet of Things for low-power gas sensors. Other gas sensors are more difficult to adapt to the environment of high humidity in coal mines. Most of the microgas sensors reported in the past use metal platinum resistors as heating elements, and the platinum resistors are also used as temperature measuring elements. Since the heating element and the temperature measuring element are the same platinum resistor, many advanced technologies for temperature measurement are restricted by the heating voltage or current applied to the platinum resistor at the same time, which limits the development of gas detection technology.

Utility model content

Technical problem: The purpose of this utility model is to provide a single-chip micro-gas sensor to solve the problem caused by the reuse of platinum wire resistance elements of existing catalytic combustion gas sensors, that is, the same platinum wire resistance can be used as a heating element and a heating element at the same time. The problem that the temperature measuring element cannot be adjusted separately when controlling the temperature and measuring the temperature.

Technical solution: the purpose of this utility model is achieved in this way: the single-chip micro gas sensor includes a catalyst carrier, a heating element, a temperature measuring element, a fixed end and a silicon frame support; the silicon frame support includes a silicon substrate and a device Buried layer of silicon oxide on the silicon substrate; the fixed end includes a supporting silicon layer, a silicon oxide layer disposed outside the supporting silicon layer, and a metal layer disposed on the silicon oxide layer as an electrical lead-out pad Pad; The supporting silicon layer of the fixed end is provided with a doped silicon layer; the metal layer of the electrical lead-out pad Pad is in contact with the doped silicon layer of the fixed end through the window of the silicon oxide layer to form an ohmic contact; the fixed end is arranged on the silicon On the buried layer of silicon oxide on the frame support; the heating element and the temperature measuring element all include a supporting silicon layer and a silicon oxide layer arranged outside the supporting silicon layer; the heating element is provided with a silicon heater, two symmetrically arranged silicon Cantilever; the silicon heater is preferably circular, and two symmetrical heat dissipation-supporting silicon blocks are preferably provided in the middle of the circular silicon heater; one end of the silicon cantilever is connected with the silicon heater, and the other One end is connected with the fixed end on the silicon frame support; the silicon heater of the heating element is provided with a catalyst carrier, the silicon heater of the heating element is completely embedded in the catalyst carrier, and the catalyst carrier runs through the silicon heater, especially The catalyst carrier is an integral structure; the temperature measuring element is provided with a silicon temperature measuring ring, two symmetrically arranged silicon connecting arms, and two symmetrically arranged silicon supporting arms; the silicon temperature measuring ring, the silicon connecting arm, the silicon The support arm and the fixed end are connected in sequence; the heating element and the temperature measuring element form independent two-terminal device paths with their respective fixed ends, and are fixed on the buried silicon oxide on the silicon frame support through the fixed ends;

The edge distance between the silicon temperature measuring ring of the temperature measuring element and the silicon heater of the heating element is 3um to 100um; the fixed end connected with the temperature measuring element and the fixed end connected with the heating element are preferably arranged on the silicon frame support position on the same side;

The heating element independently heats the catalyst carrier, and the temperature measuring element independently detects the temperature rise caused by the catalytic combustion of gas. The temperature measuring element is not affected by the voltage or current applied by the heating element during measurement.

Beneficial effects, due to the adoption of the above scheme, the single-chip silicon micro-gas sensor of the present invention is processed by MEMS technology, and the heating element and the temperature measuring element are released from the SOI silicon chip and suspended in the air, which greatly reduces the temperature passing through. The heat loss of the SOI silicon chip can effectively reduce the power consumption of the heating element; the heating element and the temperature measuring element are not in direct contact, and the heat released by the heating element and its catalytic combustion of gas is mainly through the heat conduction and heat radiation of the air The way is detected by the temperature measuring element on one side. The preparation method is compatible with the CMOS process, and the batch production can reduce the cost and improve the consistency. The sensor has low power consumption and high sensitivity, which can meet the needs of the coal mine environment Internet of Things for gas sensors.

Advantages: The single-chip micro-gas sensor provided by the utility model has both the heating element and the temperature measuring element fixed on the same device through the fixed end, so as to realize single-chip detection of gas; the heating element and the temperature measuring element are independent of each other and are no longer affected Due to the limitations of the multiplexing of the traditional single element heating and temperature measurement functions, the heating element can be controlled separately and the temperature measurement element can be tested separately. Regulating the heating element and the temperature measuring element separately can provide a variety of working modes for the sensor, and the configuration is simple and the work is flexible, thus improving the overall performance of the sensor.

The graphics of the heating element, temperature measuring element and other components may be different from the description of the utility model according to the actual situation of MEMS processing, and still belong to the claims of the utility model.

Description of drawings

FIG. 1 is a schematic top view of a discrete silicon device of the present invention.

Fig. 2 is a schematic top view of a discrete silicon device of the present invention loaded with a catalyst carrier.

Fig. 3 is a cross-sectional view of the fixed end of the discrete silicon device of the present invention or the discrete silicon device loaded with catalyst carrier and catalyst, that is, the cross-sectional view of A-A in Fig. 2 .

Fig. 4 is a cross-sectional view of a discrete silicon device of the present invention loaded with a catalyst carrier, that is, a cross-sectional view along B-B in Fig. 2 . the

Detailed ways

An embodiment of the present utility model is further described below in conjunction with accompanying drawing:

As shown in Fig. 1 and Fig. 2, the monolithic microgas sensor of the present utility model includes a catalyst carrier 105, a heating element 103, a temperature measuring element 104, a fixed end 102 and a silicon frame support 101; the silicon frame support 101 includes Silicon substrate 11 and the buried silicon oxide layer 12 disposed on the silicon substrate 11; the fixed end 102, as shown in Figure 3, includes a supporting silicon layer 21, a silicon oxide layer 23 arranged outside the supporting silicon layer 21, and The metal layer 22 used as the electrical lead-out pad Pad on the silicon oxide layer 23; the supporting silicon layer 21 of the fixed end 102 is provided with a doped silicon layer 24; the metal layer 22 of the electric lead-out pad Pad passes through The window of the silicon oxide layer 23 is in contact with the doped silicon layer 24 of the fixed end 102 to form an ohmic contact; the fixed end 102 is arranged on the buried silicon oxide 12 on the silicon frame support 101; the heating element 103, measuring The temperature elements 104 all include a supporting silicon layer 21 and a silicon oxide layer 23 outside the supporting silicon layer 21; the heating element 103 is provided with a silicon heater 1031 and two symmetrically arranged silicon cantilevers 1032; the silicon heater 1031 is preferably It is circular, and two symmetrical heat dissipation-supporting silicon blocks 1033 are preferably provided in the middle of the circular silicon heater 1031; one end of the silicon cantilever 1032 is connected with the silicon heater 1031, and the other end is connected with the silicon frame support. The fixed ends 102 on the seat 101 are connected; the silicon heater 1031 of the heating element 103 is provided with a catalyst carrier 105, and the silicon heater 1031 of the heating element 103 is completely embedded in the catalyst carrier 105, and the catalyst carrier 105 runs through the silicon heater. In the device 1031, especially the catalyst carrier 105 is an integral structure, as shown in Figure 4; the temperature measuring element 104 is provided with a silicon temperature measuring ring 1041, two symmetrically arranged silicon connecting arms 1042, and two symmetrically arranged silicon connecting arms 1042. The supporting arm 1043; the silicon temperature measuring ring 1041, the silicon connecting arm 1042, the silicon supporting arm 1043, and the fixed end 102 are sequentially connected; the heating element 103, the temperature measuring element 104 and their respective fixed ends 102 form independent two-terminal device paths , and fixed on the buried silicon oxide 12 on the silicon frame support 101 through the fixed end 102;

The edge distance between the silicon temperature measuring ring 1041 of the temperature measuring element 104 and the silicon heater 1031 of the heating element 103 is 3um to 100um; Preferably set on the same side of the silicon frame support 101;

The heating element 103 independently heats the catalyst carrier 105, and the temperature measuring element 104 independently detects the temperature rise caused by the gas catalytic combustion, and the temperature measuring element 104 is not affected by the voltage or current applied by the heating element 103 during measurement.

Claims (1)

1. the micro-firedamp sensor of monolithic, is characterized in that: the micro-firedamp sensor of this monolithic comprises catalyst support (105), heating element (103), temperature element (104), stiff end (102) and silicon frame bearing (101); Described silicon frame bearing (101) comprises silicon substrate (11) and is located at the buried regions monox (12) on silicon substrate (11); Described stiff end (102) comprises support silicon layer (21), is located at and supports the outer silicon oxide layer (23) of silicon layer (21), is located at the metal level (22) of drawing pad Pad as electricity on silicon oxide layer (23); In the support silicon layer (21) of described stiff end (102), be provided with doped silicon layer (24); The metal level (22) that described electricity is drawn pad Pad is by the window of silicon oxide layer (23) and the doped silicon layer (24) of stiff end (102) the formation Ohmic contact that contacts; Described stiff end (102) is located on the buried regions monox (12) on silicon frame bearing (101); Described heating element (103), temperature element (104) include and support silicon layer (21), are located at and support the outer silicon oxide layer (23) of silicon layer (21); Heating element (103) is provided with silicon well heater (1031), two symmetrically arranged silicon cantilevers (1032); Described silicon well heater (1031) is preferably annular, the better heat radiation-support silico briquette (1033) stretched in two symmetries that is provided with in the middle of annular silicon well heater (1031); One end of described silicon cantilever (1032) is connected with silicon well heater (1031), and the other end is connected with the stiff end (102) on silicon frame bearing (101); The silicon well heater (1031) of described heating element (103) is provided with catalyst support (105), the silicon well heater (1031) of heating element (103) is embedded in catalyst support (105) completely, and catalyst support (105) is in silicon well heater (1031), and especially catalyst support (105) is an one-piece construction; Described temperature element (104) is provided with silicon firing ring (1041), two symmetrically arranged silicon linking arms (1042), two symmetrically arranged silicon sway braces (1043); Described silicon firing ring (1041), silicon linking arm (1042), silicon sway brace (1043), stiff end (102) are connected successively; Heating element (103), temperature element (104) form independently two-terminal device path with its stiff end (102) separately respectively, and are fixed on the buried regions monox (12) on silicon frame bearing (101) by stiff end (102);

The silicon firing ring (1041) of described temperature element (104) is 3um to 100um with the Edge Distance of the silicon well heater (1031) of heating element (103); The stiff end (102) being connected with temperature element (104) and the better position that is arranged on phase the same side of silicon frame bearing (101) of the stiff end (102) being connected with heating element (103);

Heating element (103) independent heating catalyst support (105), the temperature rise that temperature element (104) independent detection Yin Wasi catalytic combustion causes, is not subject to voltage that heating element (103) applies or the impact of electric current when temperature element (104) is measured.

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