CN115373072A - C-axis preferred orientation zinc-magnesium oxide ridge waveguide and manufacturing method thereof - Google Patents

Abstract

A c-axis preferred orientation zinc magnesium oxide ridge waveguide and a manufacturing method thereof are disclosed, the method comprises: preferred orientation of Zn in c-axis _l‑x Mg _x Forming a strip-shaped masking layer on the O film, wherein x is more than or equal to 0 and less than or equal to 0.3; and under the protection of the masking layer, adopting a dry etching technology to preferentially orient Zn to the c axis _1‑x Mg _x And etching the O film to form a ridge waveguide structure. Zn prepared by the invention _l‑x Mg _x The O-ridge waveguide can be applied to passive and active devices such as nonlinear waveguides, light wave couplers, waveguide modulators, waveguide switches and waveguide lasers, and has wide application prospect in the fields of integrated optics, optical interconnection and the like.

Description

C-axis preferred orientation ZnMg ridge waveguide and manufacturing method

technical field

The invention relates to the field of optoelectronics, in particular to a c-axis preferred orientation Zn _1-x Mg _x O (0≤x≤0.3) ridge waveguide and a manufacturing method thereof.

Background technique

Zn _1-x Mg _x O thin film has the characteristics of non-toxicity, low raw material cost, and tunable energy band structure. etc. have important applications. Recent research results show that c-axis preferentially oriented Zn _0.72 Mg _0.28 O thin films have second-order nonlinear susceptibility comparable to LiNbO ₃ , revealing their great application potential in the field of integrated optics such as nonlinear waveguides and electro-optic modulators.

The ridge waveguide confines the transmitted light in two directions simultaneously, and is the basis of passive and active devices such as optical couplers, waveguide modulators, waveguide switches, and waveguide lasers. In order to obtain effective applications in the field of integrated optics, etching Zn _1-x Mg _x O thin films into ridge-shaped waveguide structures with micron-scale lateral widths is a key technology that needs to be solved urgently. The currently reported etching methods only involve Zn _1-x Mg _x O thin films with a-axis preferred orientation, generally including dry method and wet method:

(1) Dry etching

The advantage of dry etching is very good control of the sidewall profile and good etching uniformity within the chip, between chips and between batches, but its disadvantage is that the plasma causes damage to the film surface. For example, J.Zhu et al. of Rutgers University in the United States used reactive ion etching (RIE) technology based on SiCl ₄ gas to etch a-axis orientation Zn _{1- x} Mg _x O (0≤x≤ 0.3) Film.

For another example, J. Tresback et al. from Lumenz Company of the United States used inductively coupled plasma-enhanced reactive ion etching (ICP-RIE) technology based on BCl ₃ and Cl ₂ mixed gases to etch the a-axis orientation Zn ₁ grown by metal-organic vapor phase epitaxy. _{- x} Mg _x O (0≤x≤0.3) films.

(2) Wet etching

The advantage of wet etching is that the process is simple and the damage to the film surface is small, and its disadvantage is that it is not easy to control the sidewall profile. For example, J.Chen et al., University of Florida, USA used HCl/H ₂ O and H ₃ PO ₄ /H ₂ O solution etching pulsed laser deposition to grow Zn _0.9 Mg _0.1 O thin films.

For another example, J. Tresback et al. from Lumenz Company of the United States used wet etching technology based on H ₃ PO ₄ /H ₂ O solution to etch a-axis orientation Zn _1-x Mg _x O (0≤ x≤0.3) film.

However, the above studies are limited to the etching rate and the effect on the composition of the film during the process of etching the a-axis preferred orientation Zn _1-x Mg _x O film, and did not involve the fabrication of sidewall profiles and ridge waveguide structures. At present, there is still a lack of etching technology for fabricating c-axis preferred orientation Zn _1-x Mg _x O (0≤x≤0.3) ridge waveguide at home and abroad.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a c-axis preferred orientation Zn _1-x Mg _x O ridge waveguide and its manufacturing method, in order to at least partially solve at least one of the above-mentioned technical problems.

To achieve the above object, the technical scheme of the present invention is as follows:

As one aspect of the present invention, there is provided a method for fabricating a Zn _1-x Mg _x O ridge waveguide with preferred c-axis orientation, comprising: forming strip-shaped masking on the Zn _1-x Mg _x O film with preferred orientation of c-axis layer, wherein 0≤x≤0.3; and under the protection of the mask layer, the c-axis preferred orientation Zn _1-x Mg _x O thin film is etched by dry etching technology to form a ridge waveguide structure.

As another aspect of the present invention, a c-axis preferred orientation Zn _1-x Mg _x O ridge waveguide obtained by the above-mentioned manufacturing method is provided.

It can be seen from the above technical solutions that the c-axis preferred orientation Zn _1-x Mg _x O ridge waveguide and its manufacturing method of the present invention have at least one or part of the following beneficial effects:

The invention adopts the c-axis preferred orientation Zn _1-x Mg _x O (0≤x≤0.3) ridge waveguide produced by dry etching technology, and utilizes its second-order nonlinear optical characteristics and the limitation of the ridge waveguide to the transmitted light , can be applied to passive and active devices such as optical wave couplers, waveguide modulators, waveguide switches, and waveguide lasers, and has broad application prospects in the fields of integrated optics and optical interconnection.

Description of drawings

Fig. 1 is the flow chart of the manufacturing method of the c-axis preferential orientation Zn _1-x Mg _x O (0≤x≤0.3) ridge waveguide of the embodiment 1 to 4 of the present invention;

Fig. 2 is the influence of Ar/(Ar+HBr) gas ratio on Zn _0.72 Mg _0.28 O film etching rate, photoresist etching rate and etching selectivity ratio in the ICP-RIE etching in the embodiment 1 of the present invention;

3 is a cross-sectional SEM image of a Zn _0.72 Mg _0.28 O thin film sample etched by Ar/(Ar+HBr)=80% gas ratio ICP-RIE in Example 1 of the present invention;

Fig. 4 is a cross-sectional SEM image of a Zn _0.72 Mg _0.28 O thin film sample before and after etching with an Ar ion beam at a sample tilt angle of 45° in Example 2 of the present invention, wherein (a) is before etching, and (b) is after etching ;

Fig. 5 is the SEM image of the Zn _1-x Mg _x O (x=0.11 or 0.28) thin film sample after adopting Ar ion beam etching at a sample tilt angle of 7° in Example 3 of the present invention, wherein (a) is Zn _0.89 Mg _0.11 Sample cross section, (b) is Zn _0.87 Mg _0.28 O sample.

Fig. 6 is the cross-sectional SEM picture of the Zn _{1- x} Mg _x O (x=0.11 or 0.28) film sample after successively adopting 45 ° and 7 ° sample tilt angle two-step Ar ion beam etching in Example 4 of the present invention, wherein (a) is Zn _0.89 Mg _0.11 sample, (b) is Zn _0.72 Mg _0.28 O sample.

Detailed ways

The invention discloses a ridge waveguide with a lateral width of 1-2 microns made of a c-axis preferred orientation Zn _1-x Mg _x O (0≤x≤0.3) film by dry etching technology, which can be applied to Passive or active devices of linear waveguides have broad application prospects in the fields of integrated optics and optical interconnection.

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

Specifically, according to some embodiments of the present invention, a method for fabricating a c-axis preferred orientation Zn _1-x Mg _x O ridge waveguide is provided, including step S1 and step S2:

Step S1: forming a strip-shaped masking layer on the c-axis preferred orientation Zn _1-x Mg _x O film, where 0≤x≤0.3; and

Step S2: under the protection of the mask layer, the c-axis preferred orientation Zn _1-x Mg _x O thin film is etched by dry etching technology to form a ridge waveguide structure.

In some embodiments, the thickness of the c-axis preferentially oriented Zn _1-x Mg _x O film in step S1 is 500-600 nm, preferably 500 nm. According to the theory of slab waveguide mode, the thickness of 500nm is the minimum thickness required for Zn _0.72 Mg _0.28 O film (refractive index at 1550nm wavelength is 1.87) as the waveguide core layer to transmit single-mode light. In addition, if the thickness is too large (>600nm), the growth quality of the Zn _{1- x} Mg _x O film will deteriorate and the transmission loss will increase.

In some embodiments, the c-axis preferred orientation Zn _1-x Mg _x O film is formed on a thermally oxidized Si(100) substrate (hereinafter referred to as SiO ₂ /Si substrate) by radio frequency magnetron sputtering, The thickness of the thermal oxide layer is 2000-3000nm. The composition x of Mg is controlled below 0.3, which is conducive to maintaining the wurtzite crystal structure.

In some embodiments, for the different dry etching techniques used in step S2, different methods and materials can be used to make the masking layer in step S1; the thickness of the masking layer is determined according to the etching depth and etching selection ratio. .

Specifically, the masking layer may be a photoresist layer prepared by a spin coating method, and the dry etching technology is an inductively coupled plasma enhanced reactive ion (ICP-RIE) etching technology based on a mixed gas of HBr and Ar. The etchant gas is beneficial to increase the slope of the film sidewall. At this time, an etching selectivity ratio of up to 0.2 and a sidewall slope of up to about 60° can be obtained, which is suitable for making a shallow ridge waveguide structure.

Alternatively, the masking layer may be a SiO ₂ layer formed by plasma enhanced chemical deposition (hereinafter referred to as PECVD), and the dry etching technique is Ar ion beam etching technique. At this time, a maximum etching selectivity of about 0.8 and a maximum sidewall slope of approximately 90° can be obtained, which is suitable for making a deep ridge waveguide structure.

In some embodiments, when the masking layer is a photoresist layer prepared by spin coating, step S1 specifically includes:

A strip-shaped photoresist masking layer is fabricated on the c-axis preferred orientation Zn _1-x Mg _x O film through a photolithography process using a photolithography plate and a photoresist.

In some embodiments, when the masking layer is a _SiO2 layer formed by PECVD, step S1 specifically includes sub-steps S11-S13:

Sub-step S11, depositing a layer of SiO ₂ on the c-axis preferred orientation Zn _1-x Mg _x O thin film by plasma enhanced chemical deposition;

Sub-step S12, using a photolithography plate and a photoresist to form a strip-shaped photoresist masking layer on the _SiO2 layer through a photolithography process; and

In sub-step S13 , under the protection of the photoresist mask layer, the SiO ₂ layer is etched by reactive ion etching technology to form a strip-shaped SiO ₂ mask layer.

Optionally, the above-mentioned photolithography process may include, for example, steps such as oxygen plasma surface treatment, adhesive evaporation, glue spin, prebaking, ultraviolet lithography, film hardening, and oxygen plasma primer removal.

In some embodiments, before step S1, it further includes: washing the c-axis preferentially oriented Zn _1-x Mg _x O film in acetone solvent, absolute alcohol solvent, and ultrapure water, and then drying. Specifically, the cleaning time is 5 minutes respectively, and the drying operation sequentially includes blowing dry with nitrogen and drying at 120°C.

In some embodiments, the process parameters of the ICP-RIE etching technique in step S2 include: a mixed gas of HBr and Ar (gas ratio 20%-80%) is introduced into the etching chamber, and the flow rate range is between 15-25 sccm The air pressure range is between 3-7mTorr, the ICP power range is between 500-1000W, the RF power range is between 250-500W, and the DC bias voltage range is between 150-250V.

In some embodiments, the process parameters of the Ar ion beam etching treatment in step S2 include: feeding Ar gas into the etching chamber, the flow range is between 15-25 sccm, the gas pressure range is between 0.5-1.5Pa, and the sample The tilt angle range is between 5-60°, the sample rotation speed range is between 5-10rpm, the beam voltage range is between 100-500V, and the beam current range is between 50-150mA.

In some embodiments, when the Ar ion beam etching technique is used in step S2, the c-axis preferred orientation Zn _1-x Mg _x O film can be further etched step by step, and the sample tilt can be gradually reduced in the step S2 angle. The "sample tilt angle" in the present invention is also the angle between the Ar ion beam and the normal line of the substrate surface of the c-axis preferred orientation Zn _1-x Mg _x O thin film sample.

For example, when etching a c-axis preferentially oriented Zn _1-x Mg _x O film in three steps, the first step uses a sample tilt angle of 60°, the second step uses a sample tilt angle of 45°, and the third step uses 7° sample tilt angle, etc., but not limited thereto.

Under the protection of SiO ₂ masking layer, using Ar ion beam to etch the c-axis preferred orientation Zn _1-x Mg _x O film step by step, the highest etching selectivity ratio of 0.99 can be realized at the same time, the sidewall slope can be controlled in a wide range, and Facilitates the removal of the _SiO2 masking layer.

According to some embodiments of the present invention, there is also provided a c-axis preferred orientation Zn _1-x Mg _x O ridge waveguide obtained by the above manufacturing method, with a lateral width of 1-2 microns.

A number of specific embodiments are listed below to describe the technical solution of the present invention in detail. It should be noted that the following specific embodiments are only for illustration, and are not intended to limit the present invention.

Example 1:

Fig. 1 is the flow chart of the manufacturing method of the c-axis preferential orientation Zn _1-x Mg _x O (0≤x≤0.3) ridge waveguide of the embodiment 1 of the present invention, as shown in Fig. 1, the manufacturing method of the present embodiment comprises:

Step A, cleaning Zn _1-x Mg _x O (0≤x≤0.3) thin film sample (film thickness about 500nm), Zn _1-x Mg _x O thin film on SiO ₂ /Si substrate by radio frequency magnetron sputtering form.

Step B, using a photolithography plate (the width and period of Cr strips are about 1700nm and 100μm respectively) and a certain company’s photoresist (model AZ6130), after oxygen plasma surface treatment, steaming adhesive, glue rejection, pre-baking, and ultraviolet light Steps such as photolithography, film hardening and oxygen plasma primer removal, on the surface of the Zn _1-x Mg _x O (0≤x≤0.3) film after step A cleaning, make periodic array strip photoresist masking layer ( The thickness is about 1000nm, the lateral width is about 1700nm, and the period is about 100μm).

In step C, the Zn _1-x Mg _x O (0≤x≤0.3) shallow ridge waveguide structure is processed by ICP-RIE technology based on the mixed gas of HBr and Ar. The Zn _1-x Mg _x O thin films were processed using the ICP-RIE equipment parameters listed in Table 1.

Table 1 ICP-RIE equipment setting parameters

Fig. 2 is the ratio of Ar/(Ar+HBr) gas (20%, 50% and 80%) in ICP-RIE etching in the embodiment 1 of the present invention to Zn _0.72 Mg _0.28 O thin film etch rate, photoresist masking layer Etching rate and etch selectivity. With the increase of Ar gas content, the etching rate of Zn _0.72 Mg _0.28 O film and photoresist mask layer decreased gradually, but the etching selectivity increased. When the Ar/(Ar+HBr) gas ratio is 80%, the etching rates of the Zn _0.72 Mg _0.28 O film and the photoresist mask layer are 19.6nm/min and 102.8nm/min respectively, and the etching selectivity reaches the maximum (about 0.2).

3 is a cross-sectional SEM image of a Zn _0.72 Mg _0.28 O thin film sample etched by ICP-RIE with Ar/(Ar+HBr)=80% gas ratio in Example 1 of the present invention. After etching, the profile of the Zn _0.72 Mg _0.28 O film presents a shallow ridge structure, and the slope of the ridge sidewall is about 60°. The root-mean-square roughness (σ _rms ) of the surface of the ridge was measured by an atomic force microscope to be about 1.8 nm.

Example 2:

As shown in Figure 1, the production method of this embodiment includes:

Step A, cleaning Zn _1-x Mg _x O (x=0.11 or 0.28) thin film (film thickness about 500nm) sample, Zn _1-x Mg _x O thin film adopts radio frequency magnetron sputtering method on SiO ₂ /Si substrate form.

In step B, a layer of SiO ₂ film (about 1000 nm in thickness) is deposited on the surface of the Zn _1-x Mg _x O (x=0.11 or 0.28) film cleaned in step A by PECVD method. Using a photolithography plate (Cr strip width and period are 1700nm and 100μm respectively) and a company’s photoresist (model AZ6130), after oxygen plasma surface treatment, steaming binder, glue rejection, pre-baking, ultraviolet lithography, hardening film and oxygen plasma to remove primer and other steps, on the surface of SiO ₂ /Zn _1-x Mg _x O (x=0.11 or 0.28) samples, make a periodic array of strip photoresist masking layers (thickness is about 1000nm, lateral The width is about 1700nm and the period is about 100μm). Using reactive ion etching technology, on the surface of Zn _1-x Mg _x O (x = 0.11 or 0.28) samples, fabricate a periodically arranged strip-shaped SiO ₂ masking layer (thickness is about 1000nm, lateral width is about 1700nm, period is about 100μm).

Step C, processing the Zn _1-x Mg _x O (x=0.11 or 0.28) deep ridge waveguide structure by Ar ion beam etching technology. The parameters of the Ar ion beam etching equipment listed in Table 2 were used to process the Zn _1-x Mg _x O thin films.

Table 2 Ar ion beam etching equipment setting parameters

slope Sample speed gas barometric pressure flow rate beam voltage beam current Etching time 45° 9rpm Ar 1Pa 18 sccm 400V 100mA 33 points

Fig. 4 is a cross-sectional SEM picture of a Zn _0.72 Mg _0.28 O film (initial thickness about 100 nm) sample before and after etching with an Ar ion beam at a sample tilt angle of 45° in Example 2 of the present invention. As shown in Figure 4(a), after reactive ion etching, a SiO ₂ masking layer with a sidewall slope close to 90° is formed on the surface of the Zn _0.72 Mg _0.28 O film. As shown in Fig. 4(b), after Ar ion beam etching, the Zn _0.72 Mg _0.28 O film not covered by the SiO ₂ masking layer was completely etched away, forming a stripe structure, and the etching rate was about 11.4nm/ min. At the same time, the slope of the ridge-shaped sidewall formed by etching is close to 90°. In addition, part of the SiO ₂ masking layer above the Zn _0.72 Mg _0.28 O strips was etched away, and the sidewall slope remained at 90°. The etch rate of the SiO ₂ mask layer is about 28.1nm/min, and the etch selectivity is about 0.41. However, the thermally oxidized _SiO2 layer under the Zn _0.72 Mg _0.28 O film was also etched, forming a small-slope ridge underneath the Zn _0.72 Mg _0.28 O ridge.

Example 3:

As shown in Figure 1, the production method of this embodiment includes:

Step A, cleaning Zn _1-x Mg _x O (x=0.11 or 0.28) film (film thickness is about 500nm) sample, Zn _1-x Mg _x O film adopts radio frequency magnetron sputtering method on SiO ₂ /Si substrate Formed on.

In step B, a layer of SiO ₂ film (about 1000 nm in thickness) is deposited on the surface of the Zn _1-x Mg _x O (x=0.11 or 0.28) film cleaned in step A by PECVD method. Using a photolithography plate (Cr strip width and period are 1700nm and 100μm respectively) and a company’s photoresist (model AZ6130), after oxygen plasma surface treatment, steaming binder, glue rejection, pre-baking, ultraviolet lithography, hardening film and oxygen plasma to remove primer and other steps, on the surface of SiO ₂ /Zn _1-x Mg _x O (x=0.11 or 0.28) samples, make a periodic array of strip photoresist masking layers (thickness is about 1000nm, lateral The width is about 1700nm and the period is about 100μm). Using reactive ion etching technology, on the surface of Zn _1-x Mg _x O (x = 0.11 or 0.28) samples, fabricate a periodically arranged strip-shaped SiO ₂ masking layer (thickness is about 1000nm, lateral width is about 1700nm, period is about 100μm).

Step C, processing the Zn _1-x Mg _x O (x=0.11 or 0.28) deep ridge waveguide structure by Ar ion beam etching technology. The parameters of the Ar ion beam etching equipment listed in Table 3 were used to process the Zn _1-x Mg _x O thin films.

Table 3 Ar ion beam etching equipment setting parameters

slope Sample speed gas barometric pressure flow rate beam voltage beam current Etching time 7° 9rpm Ar 1Pa 18 sccm 400V 100mA 33 points

5 is a cross-sectional SEM image of a Zn _1-x Mg _x O (x=0.11 or 0.28) (initial thickness of about 500 nm) sample etched by an Ar ion beam at a sample tilt angle of 7° in Example 3 of the present invention. As shown in Fig. 5(a), after Ar ion beam etching, the Zn _0.89 Mg _0.11 O film not covered by the SiO ₂ masking layer is completely etched away, forming a deep ridge structure, and the etching rate is about 18.4nm/ min. At the same time, the strip-shaped sidewall slope formed by etching is about 60°. In addition, the SiO ₂ masking layer above the Zn _0.89 Mg _0.11 O deep ridge structure is etched into a triangle shape, the etching in the middle part is about 13.0nm/min, and the etching selectivity is about 1.42. As shown in Figure 5(b), most of the Zn _0.87 Mg _0.28 O film not covered by the SiO ₂ masking layer was etched away, forming a deep ridge structure, and the etching rate was about 12.6nm/min. At the same time, the slope of the ridge-shaped sidewall formed by etching is close to 90°. In addition, the small-slope ridges as shown in Fig. 4(b) are not formed under the deep ridges whose sidewall slopes are close to 90°. In addition, the SiO ₂ masking layer above the Zn _0.87 Mg _0.28 O deep ridge structure is etched into a triangle shape, the etching in the middle part is about 16.3nm/min, and the etching selectivity is about 0.77. These results show that: (1) The Mg content in the Zn _1-x Mg _x O films affects the Ar ion beam etching rate and sidewall slope. (2) The sample tilt _angle affects the shape of the _SiO2 masking layer above the Zn1 _{- xMgxO} ridge structure and the thermally oxidized _SiO2 layer below it.

Example 4:

As shown in Figure 1, the production method of this embodiment includes:

Step A, cleaning Zn _1-x Mg _x O (x=0.11 or 0.28) film (film thickness is about 500nm) sample, Zn _1-x Mg _x O film adopts radio frequency magnetron sputtering method on SiO ₂ /Si substrate Formed on.

In step B, a layer of SiO ₂ film (about 1000 nm in thickness) is deposited on the surface of the Zn _1-x Mg _x O (x=0.11 or 0.28) film cleaned in step A by PECVD method. Using a photolithography plate (Cr strip width and period are 1700nm and 100μm respectively) and a company’s photoresist (model AZ6130), after oxygen plasma surface treatment, steaming binder, glue rejection, pre-baking, ultraviolet lithography, hardening film and oxygen plasma to remove primer and other steps, on the surface of SiO ₂ /Zn _1-x Mg _x O (x=0.11 or 0.28) samples, make a periodic array of strip photoresist masking layers (thickness is about 1000nm, lateral The width is about 1700nm and the period is about 100μm). Using reactive ion etching technology, on the surface of Zn _1-x Mg _x O (x = 0.11 or 0.28) samples, fabricate a periodically arranged strip-shaped SiO ₂ masking layer (thickness is about 1000nm, lateral width is about 1700nm, period is about 100μm).

Step C, processing the Zn _1-x Mg _x O (x=0.11 or 0.28) deep ridge waveguide structure by Ar ion beam etching technology. This process is divided into two steps. The first step uses a 45° sample tilt angle, while the second step uses a 7° sample tilt angle. The parameters of the Ar ion beam etching equipment listed in Table 4 were used to process the Zn _1-x Mg _x O thin films.

Table 4 Ar ion beam etching equipment setting parameters

6 is a cross-sectional SEM image of a Zn _1-x Mg _x O (x=0.11 or 0.28) (initial thickness of about 500 nm) sample after two-step Ar ion beam etching in Example 4 of the present invention. After reactive ion etching, a shallow ridge structure is formed under the SiO ₂ masking layer, and the slope of the ridge sidewall is close to 90°. The etching rate (13.8nm/min) of Zn _0.89 Mg _0.11 O film is higher than that of Zn _0.72 Mg _0.28 O film (9.7nm/min). In addition, part of the SiO ₂ masking layer above the Zn _0.89 Mg _0.11 O ridge structure is etched away, and the corners on both sides above it are eliminated, showing a similar arc shape, and the slope of the side wall is still maintained at 90°. The etch rate of the SiO ₂ masking layer is about 14nm/min. Its etching selectivity for Zn _0.89 Mg _0.11 O and Zn _0.72 Mg _0.28 O films is about 0.99 and 0.69, respectively. However, the etch rate of the Zn _1-x Mg _x O (x=0.11 or 0.28) film increases in the region away from the ridge, resulting in the formation of a small-slope ridge below the shallow ridge with a sidewall slope close to 90°. These results show that: (1) The Mg content in Zn _1-x Mg _x O thin films affects the etching rate of Ar ion beam. (2) The sample tilt angle affects the shape of the _SiO2 masking layer above the Zn1 _{- xMgxO} ridge structure and the thermally oxidized _SiO2 layer below it. These results reveal that: using SiO ₂ grown by PECVD as a mask layer, Zn _1-x Mg _x O (0≤x≤0.3) films can be etched by Ar ion beams with multi-step sample tilt angles, and about 0.99 The etch selectivity ratio, the sidewall slope can be controlled in a wide range, and the SiO ₂ masking layer can be removed while maintaining the sidewall slope close to 90°.

The c-axis preferred orientation Zn _1-x Mg _x O (0≤x≤0.3) ridge waveguide produced by the present invention can be applied to passive and passive devices such as nonlinear waveguides, optical wave couplers, waveguide modulators, waveguide switches, and waveguide lasers. Active devices have broad application prospects in the fields of integrated optics and optical interconnection, and play an important role in promoting the development of silicon-based optoelectronic integrated chips and other information technologies.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (10)

1. C-axis preferred orientation Zn _1-x Mg _x The manufacturing method of the O-ridge waveguide comprises the following steps:

preferred orientation of Zn in c-axis _1-x Mg _x Forming a strip-shaped masking layer on the O film, wherein x is more than or equal to 0 and less than or equal to 0.3; and

under the protection of the masking layer, adopting a dry etching technology to preferentially orient Zn to the c axis _1-x Mg _x And etching the O film to form a ridge waveguide structure.

2. The method of claim 1, wherein the c-axis preferentially oriented Zn _1-x Mg _x The thickness of the O thin film is 500 to 600nm, preferably 500nm.

3. The method according to claim 1, wherein the masking layer is a photoresist layer prepared by a spin coating method, and the dry etching technique is an inductively coupled plasma-enhanced reactive ion etching technique based on a mixed gas of HBr and Ar.

4. The method of claim 3, wherein the inductively coupled plasma enhanced reactive ion etching technique comprises: introducing a mixed gas of HBr and Ar into the etching cavity, wherein the ratio of Ar/(Ar + HBr) gas is 20-80%, the flow rate ranges from 15-25sccm, the gas pressure ranges from 3-7mTorr, the ICP power ranges from 500-1000W, the radio frequency power ranges from 250-500W, and the direct current bias voltage ranges from 150-250V.

5. The method of claim 1, wherein the masking layer is SiO formed by plasma enhanced chemical deposition ₂ And the dry etching technology is Ar ion beam etching technology.

6. The method according to claim 5, wherein said Zn is preferentially oriented in the c-axis _1-x Mg _x The forming of the strip-shaped masking layer on the O film comprises:

preferentially orienting Zn on the c axis by adopting a plasma enhanced chemical deposition method _1-x Mg _x Depositing a layer of SiO on the O film ₂ A layer;

using a photoetching plate and a photoresist to carry out photoetching process on the SiO ₂ Forming a strip-shaped photoresist masking layer on the layer; and

under the protection of the photoresist masking layer, the SiO is etched by adopting a reactive ion etching technology ₂ Etching the layer to form strip-shaped SiO ₂ A masking layer.

7. The manufacturing method according to claim 5, wherein the process parameters of the Ar ion beam etching treatment comprise: introducing Ar gas into the etching cavity, wherein the flow range is 15-25sccm, the gas pressure range is 0.5-1.5Pa, the inclination angle range of the sample is 5-60 degrees, the rotating speed range of the sample is 5-10rpm, the beam voltage range is 100-500V, and the beam current range is 50-150 mA.

8. The method according to claim 5, wherein said c-axis is preferentially oriented Zn by dry etching _1-x Mg _x The etching of the O film comprises the following steps:

etching the c-axis preferred orientation Zn step by adopting Ar ion beams _1-x Mg _x And an O film, wherein the inclination angle of the sample is gradually reduced in the step etching.

9. The method of manufacturing according to claim 1, wherein:

the c-axis preferred orientation Zn _1-x Mg _x The O film is formed on a thermal oxidation Si (100) substrate by adopting a radio frequency magnetron sputtering method; and/or

Preferred orientation of Zn in said c-axis _1-x Mg _x Before forming the strip-shaped masking layer on the O film, the manufacturing method further comprises the following steps:

preferentially orienting the c axis to Zn _1-x Mg _x The O film is washed in acetone solvent, absolute alcohol solvent, ultrapure water, and then dried.

10. C-axis preferred orientation Zn obtained by the production method of any one of claims 1 to 9 _1-x Mg _x An O-ridge waveguide.

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