CN100514562C - Making method for large-area 3C-SiC thin film of MEMS part - Google Patents

Abstract

This invention relate to a preparing method for large area 3C-SiC films used in MEMS devices including the following steps: 1, taking a substrate, 2, carrying out in-situ hydrogen etch to the epitaxially growing side of the substrate, 3, epitaxially growing a charring layer on the etched side of the substrate in a low-pressure chemical vapor deposition oven to take it as a transition layer of the substrate and 3C-SiC film suitable for preparing 3C-SiC films, 4, epitaxially growing a 3C-SiC film on the charring layer, 5, finishing the process of the film.

Description

The preparation method who is used for the large tracts of land 3C-SiC film of MEMS device

Technical field

The invention belongs to technical field of semiconductors, be meant a kind of low-pressure chemical vapor deposition preparation method that can be applied to the large tracts of land 3C-SiC film of MEMS device especially.

Background technology

Cubic-phase silicon carbide (3C-SiC) not only has excellent mechanical strength, high modulus of elasticity (higher 3 times) than silicon, and it also has good thermal stability and chemical stability, radiation hardness, high electron mobility, therefore, it is expected to become the key semiconductor material of high-performance MEMS device of future generation.

Prior art such as patent CN1393907A use the normal pressure chemical reaction method to prepare carborundum films on the SOI base material, and the film that uses oxygen and inert gas that reaction is generated is etched with the complete silicon carbide layer of acquisition.Patent 97102232.1 is used a little less than the chemical reaction method of normal pressure and is prepared carborundum films with excessive silicon source gas under the very high temperature degree.These two kinds of methods all are unfavorable for the convenient high-quality 3C-SiC film that can be applied to the MEMS device for preparing economically in large area.

Summary of the invention

The purpose of this invention is to provide a kind of method for preparing large tracts of land 3C-SiC film by low-pressure chemical vapor deposition, the method adopts semiconductor Si monocrystalline or SOI or SIMOX to make substrate, finishes the preparation of 3C-SiC film 13 in vertical (or horizontal) low-pressure chemical vapor deposition equipment by etching 41, carbonization 44 and the 45 3 big steps of growing.

A kind of preparation method who is used for the large tracts of land 3C-SiC film of MEMS device of the present invention is characterized in that, comprises the steps:

1) gets a substrate;

2) the substrate epitaxial aufwuchsplate is carried out original position hydrogen etching, used etching pressure is 40 millitorrs-100 holders, and temperature is 1100-1200 ℃, and hydrogen flowing quantity is the 5-20 standard liter/min, and etch period is 4-6 minute, is cooled to after etching is finished below 500 ℃;

3) in the low-pressure chemical vapor deposition stove on this substrate etching face epitaxial growth one carburization zone, its growth pressure is 40 millitorrs-100 holders, when substrate is heated to 500-1100 ℃ with 5-20 ℃/minute, feeding flow is the propane or the ethene of 1-10 standard ml/min, used growth temperature is 1100-1200 ℃, hydrogen flowing quantity is the 5-20 standard liter/min, time is 1-10 minute, etch period is 1-10 minute, this carburization zone is as substrate and be about to transition zone between the epitaxially grown 3C-SiC film, and this carburization zone helps preparing the 3C-SiC film;

4) epitaxial growth one 3C-SiC film on carburization zone, growth pressure is 40 millitorrs-100 holders, after the feeding speed of change propane or ethene is 1-8 standard ml/min, underlayer temperature remains to 1100-1350 ℃, feed silane, feeding speed is 0.5-4 standard ml/min, closes silane, propane behind the growth ending, is cooled to room temperature under hydrogen shield;

5) finish, finish the making of 3C-SiC film.

The film of preparation is mainly used in the MEMS device.The present invention is achieved in that adopting diameter is that the semiconductor Si monocrystalline of 2-8 inch or SOI or SIMOX make substrate, finishes the preparation of film by etching 41, carbonization 44 and the 45 3 big steps of growing in vertical (or horizontal) low-pressure chemical vapor deposition stove.Substrate 11 is placed substrate bracket 26 (or place cassette of substrates 36 with substrate 11) and fixing, vacuumize and keep that body of heater 22 (or 32) internal pressure is 40 millitorrs-100 holders in the whole process of preparation.By radio frequency heater coil 24 (or 34) heated substrate 11, during with the hydrogen etched substrate, temperature is 1100-1200 ℃, and hydrogen flowing quantity is the 5-20 standard liter/min, and etch period is 4-6 minute, is cooled to below 500 ℃ after etching is finished.Follow carbonization substrate preparation transition zone 12.Feeding flow when substrate is heated to 500-1100 ℃ with 5-20 ℃/minute is the propane or the ethene of 1-10 standard ml/min, and carburizing temperature is 1100-1200 ℃, and hydrogen flowing quantity is the 5-20 standard liter/min, and carbonization time is 1-10 minute.Carbonization can be prepared carbonization transition zone 12 after finishing on substrate 11.Carry out 3C-SiC growth for Thin Film 45 this moment immediately.After the feeding speed of change propane or ethene is 1-8 standard ml/min, underlayer temperature remains to 1100-1350 ℃, feeds silane, and feeding speed is 0.5-4 standard ml/min, behind the growth certain hour, can on carbonization transition zone 12, prepare required 3C-SiC film 13.Close silane, propane, at H ₂Be cooled to room temperature under the gas shiled.This invention can prepare the 3C-SiC film of surface-brightening, uniform resistivity, is applicable to the MEMS device.

Compared with prior art, the present invention focus on the invention be a kind of economy low-pressure chemical vapor deposition preparation technology easily.

Description of drawings

For further specifying concrete technology contents of the present invention, below in conjunction with embodiment and accompanying drawing describes in detail as after, wherein:

Fig. 1 is that film, carbonization transition zone and substrate location concern schematic diagram;

Fig. 2 is vertical low-pressure chemical vapor deposition stove and substrate modes of emplacement schematic diagram;

Fig. 3 is horizontal low-pressure chemical vapor deposition stove and substrate modes of emplacement schematic diagram;

Fig. 4 is that growth time is to the growth temperature graph of a relation.

Embodiment

See also shown in Figure 1ly, a kind of preparation method who is used for the large tracts of land 3C-SiC film of MEMS device of the present invention is characterized in that, comprises the steps:

1) gets a substrate 11, the material of this substrate 11 is semiconductor Si monocrystalline or SOI or SIMOX, the diameter of this substrate 11 is the 2-8 inch, thickness is greater than 300 microns, the aufwuchsplate indices of crystallographic plane of this substrate 11 are (100), the aufwuchsplate indices of crystallographic plane of this substrate 11 are (111), and the doping type of this substrate 11 mixes for the n type, and doped level is 10 ¹⁷-10 ²⁰Cm ^-3, the doping type of this substrate 11 mixes for the p type, and doped level is 10 ¹⁷-10 ²⁰Cm ^-3

2) substrate 11 epitaxial growth plane are carried out original position hydrogen etching;

3) in the low-pressure chemical vapor deposition stove on these substrate 11 etched surfaces epitaxial growth one carburization zone 12, this carburization zone 12 helps preparing 3C-SiC film 13 as the transition zone of substrate 11 and 3C-SiC film 13; The epitaxial growth of described carburization zone 12, its growth pressure is 40 millitorrs-100 holders, feeding flow when substrate 11 is heated to 500-1100 ℃ with 5-20 ℃/minute is the propane or the ethene of 1-10 standard ml/min, used growth temperature is 1100-1200 ℃, hydrogen flowing quantity is the 5-20 standard liter/min, and the time is 1-10 minute;

4) epitaxial growth one 3C-SiC film 13 on carburization zone 12; The growth pressure of 3C-SiC film 13 of wherein growing is 40 millitorrs-100 holders, after the feeding speed of change propane or ethene is 1-8 standard ml/min, substrate 11 temperature remain to 1100-1350 ℃, feed silane, feeding speed is 0.5-4 standard ml/min, close silane, propane behind the growth ending, under hydrogen shield, be cooled to room temperature;

The etching of wherein said substrate 11 is hydrogen etchings, and used etching pressure is 40 millitorrs-100 holders, and temperature is 1100-1200 ℃, and hydrogen flowing quantity is the 5-20 standard liter/min, and etch period is 4-6 minute, is cooled to below 500 ℃ after etching is finished.

5) finish, finish the making of 3C-SiC film.

Embodiment 1

See also shown in Figure 1, the present invention relates to a kind of preparation method of large tracts of land 3C-SiC film of the MEMS of being used for device, wherein substrate 11 is to adopt semiconductor Si monocrystal material to make substrate, its diameter is 2 inches, thickness is 400 microns, twin polishing, and the aufwuchsplate index is (100), doping type mixes for the n type, and doped level is 10 ²⁰Cm ^-3, after standard RCA clean process, the vertical diameter of packing into is 4 inches a low-pressure chemical vapor deposition stove (shown in Figure 2).Be evacuated to 40 holders, feed from air inlet pipe 21 and be preheated to 420 ℃ H ₂Gas (purity is 99.9995%), feeding speed is 5 standard liter/min, is heated to 1100 ℃ with RF-wise, is incubated to be cooled to below 500 ℃ after 5 minutes.With RF-wise and with the heating of 8 ℃/second speed, feeding purity from air inlet pipe 21 during temperature to 600 ℃ is 99.99995% propane, and feeding speed is 5 standard ml/min, is heated to 1150 ℃, is incubated 8 minutes.Changing propane, to feed speed be 1 standard ml/min, is heated to 1300 ℃ with RF-wise, and feeding purity from air inlet pipe 21 is 99.99998% silane, and feeding speed is 0.5 standard ml/min, is incubated and closes silane, propane after 120 minutes, at H ₂Be cooled to room temperature under the gas shiled, this process can be consulted Fig. 4.At this moment, the large tracts of land 3C-SiC film that can be applied to the MEMS device has prepared and has finished.

Embodiment 2

See also shown in Figure 1ly, the present invention relates to a kind of preparation method of large tracts of land 3C-SiC film of the MEMS of being used for device, adopt semiconductor SOI to make substrate 11, its diameter is 4 inches, and thickness is 500 microns, the aufwuchsplate polishing, facial index is (100), and doping type mixes for the n type, and doped level is 10 ²⁰Cm ^-3, after standard RCA clean process, the vertical diameter of packing into is 6 inches a low-pressure chemical vapor deposition stove (shown in Figure 2).Be evacuated to 40 holders, feed from air inlet pipe 21 and be preheated to 420 ℃ H2 gas (purity is 99.9995%), feeding speed is 8 standard liter/min, is heated to 1100 ℃ with RF-wise, is incubated to be cooled to below 500 ℃ after 3 minutes.With RF-wise and with the heating of 8 ℃/second speed, feeding purity from air inlet pipe 21 during temperature to 600 ℃ is 99.99995% propane, and feeding speed is 6 standard ml/min, is heated to 1100 ℃, is incubated 7 minutes.Change H ₂It is 6 standard liter/min that gas feeds speed, and changing propane feeding speed is 4 standard ml/min, is heated to 1200 ℃ with RF-wise, feeding purity from air inlet pipe 21 is 99.99998% silane, feeding speed is 2 standard ml/min, is incubated and closes silane, propane after 100 minutes, at H ₂Be cooled to room temperature under the gas shiled, this process can be consulted Fig. 4.At this moment, the large tracts of land 3C-SiC film that can be applied to the MEMS device has prepared and has finished.

Embodiment 3

See also shown in Figure 1ly, the present invention relates to a kind of preparation method of large tracts of land 3C-SiC film of the MEMS of being used for device, adopt semiconductor Si monocrystalline to make substrate 11, its diameter is 4 inches, and thickness is 450 microns, the aufwuchsplate polishing, facial index is (111), and doping type mixes for the p type, and doped level is 10 ¹⁹Cm ^-3, after standard RCA clean process, load level formula diameter is 6 inches a low-pressure chemical vapor deposition stove (shown in Figure 3).Be evacuated to 40 holders, feed from air inlet pipe 31 and be preheated to 420 ℃ H2 gas (purity is 99.9995%), feeding speed is 8 standard liter/min, is heated to 1200 ℃ with RF-wise, is incubated to be cooled to below 500 ℃ after 3 minutes.With RF-wise and with the heating of 8 ℃/second speed, feeding purity from air inlet pipe 31 during temperature to 600 ℃ is 99.99998% ethene, and feeding speed is 8 standard ml/min, is heated to 1200 ℃, is incubated 10 minutes.Changing H2 gas feeding speed is 6 standard liter/min, changing propane feeding speed is 5 standard ml/min, adjust substrate 11 temperature to 1100 ℃, feeding purity from air inlet pipe 31 is 99.99998% silane, feeding speed is 1.8 standard ml/min, be incubated and close silane, ethene after 150 minutes, at H ₂Be cooled to room temperature under the gas shiled, this process can be consulted Fig. 4.At this moment, the large tracts of land 3C-SiC film that can be applied to the MEMS device has prepared and has finished.

Claims (1)

1. a preparation method who is used for the large tracts of land 3C-SiC film of MEMS device is characterized in that, comprises the steps:

1) gets a substrate;

2) the substrate epitaxial aufwuchsplate is carried out original position hydrogen etching, used etching pressure is 40 millitorrs-100 holders, and temperature is 1100-1200 ℃, and hydrogen flowing quantity is the 5-20 standard liter/min, and etch period is 4-6 minute, is cooled to after etching is finished below 500 ℃;

3) in the low-pressure chemical vapor deposition stove on this substrate etching face epitaxial growth one carburization zone, its growth pressure is 40 millitorr 1-100 holders, when substrate is heated to 500-1100 ℃ with 5-20 ℃/minute, feeding flow is the propane or the ethene of 1-10 standard ml/min, used growth temperature is 1100-1200 ℃, hydrogen flowing quantity is the 5-20 standard liter/min, time is 1-10 minute, etch period is 1-10 minute, this carburization zone is as substrate and be about to transition zone between the epitaxially grown 3C-SiC film, and this carburization zone helps preparing the 3C-SiC film;

4) epitaxial growth one 3C-SiC film on carburization zone, growth pressure is 40 millitorrs-100 holders, after the feeding speed of change propane or ethene is 1-8 standard ml/min, underlayer temperature remains to 1100-1350 ℃, feed silane, feeding speed is 0.5-4 standard ml/min, closes silane, propane behind the growth ending, is cooled to room temperature under hydrogen shield;

5) finish, finish the making of 3C-SiC film.

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