Vibration piece

Abstract

To provide a vibration piece having high oscillation stability.SOLUTION: A resonator element includes a base portion and three vibrating arms extending from the base portion in a first direction and arranged side by side in a second direction orthogonal to the first direction, and each of the three vibrating arms includes an arm portion extending from the base portion and a wide portion located on a distal end side of the arm portion and wider than the arm portion. W1 is a length along the second direction of the arm portion included in the vibrating arm located at the center of the arrangement among the three vibrating arms. A relationship of 1 ≤ W2 / W1 ≤ 2 is satisfied when widths that are lengths along the second direction of the arm portions included in the vibrating arms located at both ends of the array are W2, and a relationship of Lh / L ≤ 0.49 is satisfied when a length along the first direction of the vibrating arm is L and a length along the first direction of the wide portion is Lh for each of the three vibrating arms.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a vibrating piece.

Background Art

[0002] The silicon vibrating piece described in Patent Document 1 has a base portion and three vibrating arms extending in the Y-axis direction from the base portion. Further, the three vibrating arms are arranged in the X-axis direction orthogonal to the Y-axis direction and have piezoelectric elements on the upper surface. Then, when the piezoelectric element to which a driving voltage is applied expands and contracts, each vibrating arm vibrates in the Z-axis direction orthogonal to the X-axis and the Y-axis. Further, when the arm width of the vibrating arm located at the center of the arrangement is W1 and the arm widths of the two vibrating arms located at both ends of the arrangement are each W among the three vibrating arms, by setting the relationship of 1.35 < W1 / W < 1.90, deterioration of the Q value is suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, Patent Document 1 does not disclose a configuration in which a wide portion is formed at the tip of each vibrating arm, and the conditions for suppressing deterioration of the Q value in a vibrating piece having a wide portion are unknown.

Means for Solving the Problems

[0005] The vibrating piece according to the present invention has a base portion and three vibrating arms extending in a first direction from the base portion and arranged side by side in a second direction orthogonal to the first direction. Each of the three vibrating arms has an arm portion extending from the base portion and a wide portion located on the tip side of the arm portion and wider than the arm portion. When the width of the three vibrating arms, which is the length along the second direction of the arm portion of the vibrating arm located at the center of the arrangement, is W1, and the width of the arm portion of the vibrating arms located at both ends of the arrangement, which is the length along the second direction of the arm portion, is W2, the relationship 1≦W1 / W2≦2 is satisfied, For each of the three vibrating arms, when the length of the vibrating arm along the first direction is L and the length of the wide portion along the first direction is Lh, the relationship Lh / L≦0.49 is satisfied. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a plan view of a MEMS device according to a preferred embodiment; [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 2 is a plan view of a vibrating element included in the MEMS element. [Figure 4] FIG. 2 is a cross-sectional view of a vibrating arm of the vibrator element. [Figure 5] 10 is a graph showing the relationship between W1 / W2 and the Q value. [Figure 6] 1 is a graph showing the relationship between Lh / L and the Q value. DETAILED DESCRIPTION OF THE INVENTION

[0007] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The resonator element of the present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings.

[0008] FIG. 1 is a plan view of a MEMS element according to a preferred embodiment. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. FIG. 3 is a plan view of a vibrating element included in the MEMS element. FIG. 4 is a cross-sectional view of a vibrating arm included in the vibrating element. FIG. 5 is a graph showing the relationship between W1 / W2 and the Q value. FIG. 6 is a graph showing the relationship between Lh / L and the Q value.

[0009] For ease of explanation, each of Figures 1 to 45 illustrates an X-axis, a Y-axis, and a Z-axis, which are perpendicular to one another. The direction along the X-axis is also referred to as the X-axis direction, the direction along the Y-axis as the Y-axis direction, and the direction along the Z-axis as the Z-axis direction. The X-axis direction corresponds to the "second direction," and the Y-axis direction corresponds to the "first direction." The arrowed side of each axis is also referred to as the "plus side," and the opposite side as the "minus side." The plus side of the Z-axis is also referred to as the "upper," and the minus side as the "lower."

[0010] As shown in FIGS. 1 and 2, the MEMS element 1 includes an SOI (Silicon on Insulator) substrate 10 on which a resonator element 20 is formed, and a lid 5 that hermetically seals the resonator element 20 between the SOI substrate 10. The lid 5 is made of single crystal silicon or the like and has a recess that opens to its bottom surface. The bottom surface of the lid 5 is bonded to the top surface of the SOI substrate 10. As shown in FIG. 2, the SOI substrate 10 is a multilayer substrate in which a silicon layer 11 serving as a handle layer, a BOX (Buried Oxide) layer 12, and a surface silicon layer 13 serving as a device layer are stacked in this order from the bottom. For example, the silicon layer 11 and the surface silicon layer 13 are each made of single crystal silicon, and the BOX layer 12 is made of a silicon oxide (SiO2) layer.

[0011] 1, the surface silicon layer 13 is formed with a vibrating substrate 21 provided on the vibrating element 20 and a frame-shaped frame portion 131 surrounding the periphery of the vibrating substrate 21. A pair of electrode pads PAD1 and PAD2 are disposed on the upper surface of the frame portion 131. As shown in FIG. 2, through electrodes 14 and 15 that penetrate the SOI substrate 10 in the thickness direction are formed at positions overlapping with the electrode pads PAD1 and PAD2. The through electrode 14 is electrically connected to the electrode pad PAD1, and the through electrode 15 is electrically connected to the electrode pad PAD2. This allows the electrode pads PAD1 and PAD2 to be drawn out from the lower surface of the MEMS element 1. This facilitates electrical connection with an external device such as an oscillator circuit.

[0012] Furthermore, the vibrating element 20 has a vibrating substrate 21 formed on the surface silicon layer 13. That is, the vibrating substrate 21 is formed from a silicon substrate. By forming the vibrating substrate 21 from a silicon substrate, the vibrating substrate 21 can be formed using a silicon wafer process, which makes it easy to process the vibrating substrate 21 and allows the vibrating substrate 21 to be formed with high processing accuracy.

[0013] The vibration substrate 21 is plate-shaped and has an upper surface and a lower surface that are opposite surfaces. As shown in FIG. 3, the vibration substrate 21 has a base 210 and three vibrating arms 22A, 22B, and 22C extending from the base 210. As shown in FIG. 4, the base 210 is supported by the silicon layer 11 and the BOX layer 12 located below, whereas the vibrating arms 22A, 22B, and 22C are separated from the BOX layer 12. Therefore, the vibrating arms 22A, 22B, and 22C are cantilever beams that are cantilevered at their base ends on the base 210. The entire vibration substrate 21 is formed to have the same thickness as the surface silicon layer 13.

[0014] 3, the vibrating arms 22A, 22B, and 22C each extend from the base 210 toward the positive side of the Y-axis direction, which is a first direction, and are arranged side by side at equal intervals in the X-axis direction, which is a second direction. Specifically, the vibrating arm 22A is located in the center of the arrangement, the vibrating arm 22B is located on the positive side of the X-axis direction of the vibrating arm 22A, and the vibrating arm 22C is located on the negative side of the X-axis direction. Each of the vibrating arms 22A, 22B, and 22C has an arm portion 221 extending from the base 210 toward the positive side of the Y-axis direction, and a wide portion 222 that is located on the tip side of the arm portion 221 and is wider than the arm portion 221. Note that, hereinafter, for convenience of explanation, the length of each of the vibrating arms 22A, 22B, and 22C along the Y-axis direction will be referred to as the "length," and the length along the X-axis direction will be referred to as the "width."

[0015] Each arm 221 is straight and has a constant width along the Y-axis direction. The width of the wide portion 222 is greater than the width of the arm 221. Each wide portion 222 is straight and has a constant width along the Y-axis direction. With this configuration, the mass of the tip of each of the vibrating arms 22A, 22B, and 22C increases due to the mass effect of the wide portion 222. Therefore, if the resonant frequency of the vibrating arm 20 is the same, the overall length of the vibrating arms 22A, 22B, and 22C can be shortened compared to when the wide portion 222 is not present, thereby enabling the miniaturization of the vibrating arm 20. Alternatively, if the overall length of the vibrating arms 22A, 22B, and 22C is the same, the resonant frequency of the vibrating arm 20 can be lowered compared to when the wide portion 222 is not present.

[0016] The vibrating element 20 also has a film-like weight M disposed on the upper surface of the wide portion 222 of each vibrating arm 22A, 22B, and 22C. By disposing the weight M, the mass of the wide portion 222 increases, making the aforementioned mass effect more pronounced. The material constituting the weight M is not particularly limited, but preferably includes at least one of aluminum (Al), titanium (Ti), chromium (Cr), gold (Au), silver (Ag), copper (Cu), and polysilicon (Si). The term "aluminum (Al)" includes aluminum compounds such as aluminum oxide and aluminum nitride, in addition to aluminum. The same applies to the other materials mentioned above. Although not shown, the weight M of this embodiment has a structure in which a gold (Au) surface layer is laminated on a titanium (Ti) base layer. Using these materials allows for easy formation of a weight M with a high specific gravity. However, the weight M may be omitted.

[0017] 2 and 3, the vibrating element 20 has a temperature characteristic adjusting section 24 that adjusts the frequency temperature characteristic of the resonant frequency. The temperature characteristic adjusting section 24 has a temperature characteristic adjusting film 24A arranged on the upper surface of the vibrating arm 22A, a temperature characteristic adjusting film 24B arranged on the upper surface of the vibrating arm 22B, and a temperature characteristic adjusting film 24C arranged on the upper surface of the vibrating arm 22C.

[0018] As shown in FIG. 4, the temperature characteristic adjustment films 24A, 24B, and 24C are disposed across the base 210 and the arm 221. In other words, the temperature characteristic adjustment films 24A, 24B, and 24C are disposed so as to overlap the boundary between the base 210 and the arm 221. The temperature characteristic adjustment films 24A, 24B, and 24C are configured as a laminate of a first layer 241, which is a silicon oxide (SiO2) layer, and a second layer 242, which is a zirconium oxide (ZrO2) layer, and this laminate is further covered with a polysilicon layer 243 as a coating layer. Silicon, which is the constituent material of the vibration substrate 21, has a frequency-temperature characteristic in which the resonant frequency decreases as the temperature increases. On the other hand, silicon oxide (SiO2) and zirconium oxide (ZrO2) have a frequency-temperature characteristic in which the resonant frequency increases as the temperature increases. Therefore, these frequency-temperature characteristics are canceled out, and the frequency-temperature characteristics of the resonant frequency of the composite formed by the vibrating arms 22A, 22B, and 22C and the temperature characteristic adjusting films 24A, 24B, and 24C can be made closer to flat. For example, the variation in the resonant frequency of the vibrating substrate 21, which is approximately ±3,000 ppm in the temperature range from -25°C to +75°C, can be flattened to approximately ±200 ppm to ±500 ppm by arranging the temperature characteristic adjusting portion 24.

[0019] The configuration of the temperature characteristic adjustment films 24A, 24B, and 24C is not particularly limited, and they may be configured with only either the first layer 241 or the second layer 242. They may also include another layer in addition to the first and second layers 241 and 242. The temperature characteristic adjustment portion 24 may also be omitted.

[0020] As shown in FIG. 3, the vibrating element 20 includes a driving unit 23 that bends and deforms the vibrating arms 22A, 22B, and 22C in the Z-axis direction. The driving unit 23 includes a piezoelectric element 23A that is overlaid on a temperature characteristic adjustment film 24A and disposed on the upper surface of the vibrating arm 22A, a piezoelectric element 23B that is overlaid on a temperature characteristic adjustment film 24B and disposed on the upper surface of the vibrating arm 22B, and a piezoelectric element 23C that is overlaid on a temperature characteristic adjustment film 24C and disposed on the upper surface of the vibrating arm 22C. The piezoelectric elements 23A, 23B, and 23C are shorter than the arm portion 221 and are disposed in approximately half of the base ends of the vibrating arms 22A, 22B, and 22C. Furthermore, the piezoelectric elements 23A, 23B, and 23C are shorter than the length L of the vibrating arms 22A, 22B, and 22C, and in this embodiment, are disposed in approximately half of the base ends of the vibrating arms 22A, 22B, and 22C. Furthermore, the piezoelectric elements 23A, 23B, and 23C are arranged across the base 210 and the arm 221. To balance the vibrations, in the vibrator element 20, at least the vibrating arms 22B and 22C located at both ends of the arrangement have the same configuration (shape, size), and the central vibrating arm 22A has a different configuration (shape, size) from the vibrating arms 22B and 22C as necessary. This will be described in detail later.

[0021] Such piezoelectric elements 23A, 23B, and 23C each expand and contract in the Y-axis direction when a drive voltage is applied. By expanding and contracting piezoelectric elements 23A, 23B, and 23C in the Y-axis direction, vibrating arms 22A, 22B, and 22C flexurally vibrate in the Z-axis direction.

[0022] 4, each of the piezoelectric elements 23A, 23B, and 23C has a lower electrode 231, a piezoelectric layer 232 disposed on the upper surface of the lower electrode 231, and an upper electrode 233 disposed on the upper surface of the piezoelectric layer 232. The materials constituting each of the piezoelectric elements 23A, 23B, and 23C are not particularly limited, but for example, the piezoelectric layer 232 is made of aluminum nitride (AlN) or the like, and the lower electrode 231 and the upper electrode 233 are made of titanium nitride (TiN) or the like. However, the configuration of the piezoelectric elements 23A, 23B, and 23C is not particularly limited, and another layer may be interposed between each layer.

[0023] 3, the piezoelectric elements 23A, 23B, and 23C are wired so that adjacent vibrating arms 22A, 22B, and 22C flex and vibrate in opposite phases. That is, the piezoelectric elements 23A, 23B, and 23C are wired so that a first state in which the vibrating arms 22B and 22C flex and deform upward and the vibrating arm 22A flexes and deforms downward, and a second state in which the vibrating arms 22B and 22C flex and deform downward and the vibrating arm 22A flexes and deforms upward are alternately repeated. Specifically, the lower electrodes 231 of the piezoelectric elements 23B and 23C and the upper electrode 233 of the piezoelectric element 23A are electrically connected to the electrode pad PAD1 via wiring (not shown), and the upper electrodes 233 of the piezoelectric elements 23B and 23C and the lower electrode 231 of the piezoelectric element 23A are electrically connected to the electrode pad PAD2 via wiring (not shown).

[0024] In this way, by causing adjacent vibrating arms 22A, 22B, and 22C to flexurally vibrate in opposite phases to each other, at least a portion of the vibrations of vibrating arms 22A, 22B, and 22C are canceled, effectively suppressing vibration leakage from vibrating element 20. The flexural vibration of vibrating arms 22A, 22B, and 22C is greatly excited at the resonant frequency, minimizing impedance. As a result, by connecting this MEMS element 1 to an oscillation circuit, an oscillator that oscillates at an oscillation frequency determined by the resonant frequency is obtained.

[0025] The overall configuration of the vibrating element 20 has been described above. Next, the dimensions of the vibrating element 20 will be described in detail. As shown in Fig. 3, when the width of the arm portion 221 of the vibrating arm 22A located at the center of the arrangement of three vibrating arms 22A, 22B, and 22C is defined as W1, and the width of the arm portions 221 of the vibrating arms 22B and 22C located at both ends of the arrangement is defined as W2, the relationship 1 ≤ W1 / W2 ≤ 2 is satisfied. Furthermore, among the above relationships, in this embodiment, the relationship 1.6 ≤ W1 / W2 ≤ 2.0 is particularly satisfied.

[0026] The reason for this is explained below. In the vibrating element 20, the vibrating arms 22A, 22B, and 22C deform linearly in response to the force applied by the expansion and contraction of the piezoelectric elements 23A, 23B, and 23C. In other words, the greater the expansion and contraction of the piezoelectric elements 23A, 23B, and 23C, the greater the amplitude of the vibrating arms 22A, 22B, and 22C. However, when a force greater than a certain level is applied, the spring rigidity of the vibrating arms 22A, 22B, and 22C appears to increase, making it difficult for the vibrating arms 22A, 22B, and 22C to deform. In other words, the linear relationship between the force applied to the vibrating arms 22A, 22B, and 22C and the deformation of the vibrating arms 22A, 22B, and 22C is lost. This phenomenon is also called spring nonlinearity. Nonlinearity increases fluctuations in the vibration frequency of the vibrating element 20 or causes the vibrating element 20 to suddenly stop oscillating, thereby affecting oscillation stability. Therefore, it is preferable to use the vibrating element 20 in a region where no nonlinearity appears or where the nonlinearity is small.

[0027] While this nonlinearity problem exists, as described above, in the vibrating element 20, the central vibrating arm 22A and the vibrating arms 22B and 22C at both ends vibrate in opposite phases. If there is a difference between the total mass M1 (the mass of the vibrating arm 22B plus the mass of the vibrating arm 22C) of the vibrating arms 22B and 22C, which vibrate in the same phase, and the mass M2 of the vibrating arm 22A, which vibrates in opposite phase to the total mass M1, the lighter vibrating arm vibrates more strongly than the heavier vibrating arm. In this way, if only some of the three vibrating arms 22A, 22B, and 22C vibrate more strongly, these arms reach the nonlinear region before the other arms, causing the nonlinearity described above to appear earlier. In other words, the nonlinearity appears at a lower driving voltage. Therefore, in order to make nonlinearity less likely to occur, for example, it is advisable to make the width W1 of the vibrating arm 22A larger than the width W2 of each of the vibrating arms 22B and 22C, thereby sufficiently reducing the difference between the total mass M1 and the mass M2, and to make the amplitudes of the vibrating arms 22A, 22B, and 22C approximately the same as each other.

[0028] However, as shown in FIG. 5, as W1 / W2, the ratio of widths W1 and W2, increases, the Q value of the vibrating element 20 decreases. In other words, if W1 / W2 is made too large to reduce the likelihood of nonlinearity, the Q value of the vibrating element 20 decreases, which also affects the oscillation stability of the vibrating element 20. Therefore, the ratio W1 / W2 of the vibrating element 20 is set to 1≦W1 / W2≦2. This configuration makes it possible to reduce the likelihood of nonlinearity while maintaining a sufficiently high Q value. Furthermore, by setting W1 / W2 to 1.6≦W1 / W2≦2.0 as in this embodiment, nonlinearity is further reduced, and the above-mentioned effect becomes more pronounced.

[0029] Furthermore, as shown in FIG. 6, the Q value of the vibrating element 20 decreases as the ratio of the length Lh of the wide portion 222 to the length L of the vibrating arms 22A, 22B, and 22C increases. Therefore, in the vibrating element 20, to ensure that the Q value is 10,000 or more, which is a guideline for oscillation stability, Lh / L≦0.49 is set for each of the vibrating arms 22A, 22B, and 22C. This configuration allows the Q value to be maintained sufficiently high. As described above, by satisfying 1≦W1 / W2≦2 and Lh / L≦0.49, the Q value can be maintained sufficiently high while nonlinearity is less likely to occur. This results in a vibrating element 20 with high oscillation stability.

[0030] Although the lower limit of Lh / L is not particularly limited, it is preferable that it be 0.2≦Lh / L, which prevents the wide portion 222 from becoming excessively small and allows the mass effect of the wide portion 222 to be fully exerted, thereby enabling the vibrating element 20 to be miniaturized.

[0031] The above has described the MEMS element 1. As described above, the vibrating element 20 included in such a MEMS element 1 has a base 210 and three vibrating arms 22A, 22B, and 22C that extend from the base 210 in the Y-axis direction, which is a first direction, and are arranged side by side in the X-axis direction, which is a second direction perpendicular to the Y-axis direction. Each of the three vibrating arms 22A, 22B, and 22C has an arm portion 221 extending from the base 210 and a wide portion 222 that is located on the tip side of the arm portion 221 and is wider than the arm portion 221. Furthermore, when the width along the X-axis direction of the arm portion 221 of the resonating arm 22A located at the center of the arrangement among the three resonating arms 22A, 22B, and 22C is defined as W1, and the width along the X-axis direction of the arm portion 221 of the resonating arms 22B and 22C located at both ends of the arrangement is defined as W2, the relationship 1≦W1 / W2≦2 is satisfied. For each of the three resonating arms 22A, 22B, and 22C, when the length along the Y-axis direction of the resonating arms 22A, 22B, and 22C is defined as L, and the length along the Y-axis direction of the wide portion 222 is defined as Lh, the relationship Lh / L≦0.49 is satisfied. This configuration can maintain a sufficiently high Q value while reducing the likelihood of nonlinearity. This results in a resonator element 20 with high oscillation stability.

[0032] As described above, 0.2≦Lh / L is satisfied in the vibrator element 20. With this configuration, the vibrator element 20 can be made smaller.

[0033] As described above, the vibrating element 20 has a film-shaped weight portion M disposed on each wide portion 222. With this configuration, the wide portion 222 can be made heavier, and the mass effect of the wide portion 222 becomes more pronounced.

[0034] As described above, the material of the weight portion M includes at least one of aluminum, titanium, chromium, gold, silver, copper, and polysilicon. With this configuration, it is possible to easily form the weight portion M with a high specific gravity. Therefore, the mass effect of the wide portion 222 becomes more pronounced.

[0035] As described above, the vibrating element 20 has a driving unit 23 disposed on each arm 221, which flexes and deforms each of the vibrating arms 22A, 22B, and 22C in the Z-axis direction, which is a third direction perpendicular to the Y-axis direction and the X-axis direction. With this configuration, the vibrating arms 22A, 22B, and 22C can be flexurally vibrated efficiently.

[0036] As described above, the driving section 23 is disposed across each arm section 221 and the base section 210. With this configuration, the vibrating arms 22A, 22B, and 22C can be more efficiently subjected to bending vibration.

[0037] As described above, the vibrating element 20 has the temperature characteristic adjusting portion 24 that is disposed on each arm portion 221 and adjusts the frequency-temperature characteristic. With this configuration, the frequency-temperature characteristic of the vibrating substrate 21 can be improved.

[0038] While the vibrating element of the present invention has been described above based on the illustrated embodiment, the present invention is not limited thereto. The configuration of each part can be replaced with any configuration having a similar function. Furthermore, any other configuration may be added to the present invention. For example, in the above-described embodiment, the vibrating substrate 21 is made of silicon, but this is not limited thereto. For example, it may be made of quartz or a piezoelectric material other than quartz. In this case, the driving unit may be composed of electrodes arranged on the vibrating substrate 21. [Explanation of symbols]

[0039] 1...MEMS element, 10...SOI substrate, 11...silicon layer, 12...BOX layer, 13...surface silicon layer, 131...frame portion, 14...through electrode, 15...through electrode, 20...vibration element, 21...vibration substrate, 210...base portion, 22A...vibration arm, 22B...vibration arm, 22C...vibration arm, 221...arm portion, 222...wide portion, 23...drive portion, 23A...piezoelectric element, 23B...piezoelectric element, 23C... Piezoelectric element, 231...lower electrode, 232...piezoelectric layer, 233...upper electrode, 24...temperature characteristic adjustment portion, 24A...temperature characteristic adjustment film, 24B...temperature characteristic adjustment film, 24C...temperature characteristic adjustment film, 241...first layer, 242...second layer, 243...polysilicon film, 5...lid portion, M...weight portion, L...length, Lh...length, PAD1...electrode pad, PAD2...electrode pad, W1...width, W2...width

Claims

1. A base and three vibrating arms extending from the base in a first direction and arranged side by side in a second direction perpendicular to the first direction; Each of the three vibrating arms has an arm portion extending from the base portion and a wide portion located at a tip end side of the arm portion and wider than the arm portion, When the width of the resonating arm located at the center of the arrangement among the three resonating arms is W1, which is the length along the second direction of the arm portion of the resonating arm located at both ends of the arrangement, is W2, the relationship of 1≦W1 / W2≦2 is satisfied, A vibrating piece characterized in that, for each of the three vibrating arms, when the length of the vibrating arm along the first direction is L and the length of the wide portion along the first direction is Lh, the relationship Lh / L≦0.49 is satisfied.

2. 2. The vibrator element according to claim 1, wherein 0.2≦Lh / L.

3. The vibrator element according to claim 1 , further comprising a film-shaped weight portion disposed on each of the wide portions.

4. The vibrator element according to claim 3 , wherein the weight portion is made of a material containing at least one of aluminum, titanium, chromium, gold, silver, copper, and polysilicon.

5. The vibrator element according to claim 1 , further comprising a driving section disposed on each of the arms to bend and deform each of the vibrating arms in a third direction perpendicular to the first direction and the second direction.

6. The vibrator element according to claim 5 , wherein the driving portion is disposed across each of the arm portions and the base portion.

7. The resonator element according to claim 1 , further comprising a temperature characteristic adjusting portion disposed on each of the arms for adjusting a frequency-temperature characteristic.

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