Anchors for microelectromechanical systems having an SOI substrate, and method of fabricating same

• US 20050253209A1
• Filed: 06/21/2005
• Published: 11/17/2005
• Est. Priority Date: 07/25/2003
• Status: Active Grant

• Current Assignee: Aaron Partridge, Markus Lutz, Silvia Kronmueller
• Original Assignee: Aaron Partridge, Markus Lutz, Silvia Kronmueller
• Inventors: Partridge, Aaron, Lutz, Markus, Kronmueller, Silvia
• Granted Patent: US 7,317,233 B2
• Time in Patent Office: Days
• US Class Current: 257/415
• CPC Class Codes: B81B 2203/0307 Anchors
• CPC Class Codes: B81B 3/0054 For holding or placing an element in a given position
• CPC Class Codes: B81C 1/00126 Static structures not provided for in groups B81C1/00031 - B81C1/00119

Abstract

There are many inventions described and illustrated herein. In one aspect, the present invention is directed to a MEMS device, and technique of fabricating or manufacturing a MEMS device having mechanical structures and anchors to secure the mechanical structures to the substrate. The anchors of the present invention are comprised of a material that is relatively unaffected by the release processes of the mechanical structures. In this regard, the etch release process are selective or preferential to the material(s) securing the mechanical structures in relation to the material comprising the anchors. Moreover, the anchors of the present invention are secured to the substrate in such a manner that removal of the insulation layer has little to no affect on the anchoring of the mechanical structures to the substrate.

Claims

1-64. -64. (canceled)

65. A microelectromechanical device comprising:

a substrate;

an insulation layer disposed on the substrate;

a first semiconductor layer disposed on or above the insulation layer;

an anchor that is disposed in an opening in the insulation layer and the first semiconductor layer and contacts the substrate, wherein the anchor includes a material that is different from the insulation layer;

a second semiconductor layer disposed on the anchor;

a fixed electrode, formed, in part, from the first and second semiconductor layers, wherein the fixed electrode is affixed to the substrate via the anchor;

a moveable electrode, formed, in part, from the second semiconductor layer, wherein the moveable electrode is disposed, at least in part, in a chamber;

a first encapsulation layer disposed over the moveable electrode, wherein the first encapsulation layer is at least a portion of a wall of the chamber; and

a second encapsulation layer, deposited on the first encapsulation layer, to seal the chamber.

66. The device of claim 65 wherein the insulation layer includes silicon nitride or silicon oxide.

67. The device of claim 65 wherein the insulation layer includes silicon oxide and the anchor material includes silicon nitride, silicon carbide, germanium, silicon/germanium or gallium arsenide.

68. The device of claim 65 wherein the insulation layer includes silicon nitride and the anchor material includes silicon, silicon oxide, silicon carbide, germanium, silicon/germanium or gallium arsenide.

69. The device of claim 65 wherein a substantial portion of the fixed electrode overlying the anchor material includes a monocrystalline silicon.

70. The device of claim 65 wherein a substantial portion of the fixed electrode overlying the anchor material includes a polycrystalline silicon.

71. The device of claim 65 further including a third encapsulation layer disposed on the second encapsulation layer.

72. The device of claim 71 wherein the third encapsulation layer is a metal material including aluminum, chromium, gold, silver, molybdenum, platinum, palladium, tungsten, titanium, silicide and/or copper.

73. The device of claim 71 wherein the third encapsulation layer is an insulating material including silicon oxide, silicon nitride, BPSG, PSG and/or SOG.

74. A microelectromechanical device comprising:

a substrate;

an insulation layer disposed on the substrate;

a first semiconductor layer disposed on or above the insulation layer;

an anchor that is disposed in an opening in the insulation layer and the first semiconductor layer and contacts the substrate, wherein the anchor includes a material that is different from the insulation layer;

a second semiconductor layer disposed on the anchor and on the first semiconductor layer;

a fixed electrode, formed, in part, from the first and second semiconductor layers, wherein the fixed electrode is affixed to the substrate via the anchor;

a moveable electrode, formed, in part, from the second semiconductor layer, wherein the moveable electrode is disposed, at least in part, in a chamber;

a first encapsulation layer, disposed over at a portion of the moveable electrode, wherein the first encapsulation layer is at least a portion of a wall of the chamber; and

a second encapsulation layer, deposited on the first encapsulation layer, to seal the chamber, wherein the second encapsulation layer includes a semiconductor material.

75. The device of claim 74 wherein the first encapsulation layer includes a porous semiconductor material.

76. The device of claim 74 wherein the second encapsulation layer includes polycrystalline silicon, silicon carbide, silicon/germanium, germanium, or gallium arsenide.

77. The device of claim 74 wherein the insulation layer includes silicon oxide and the anchor material includes silicon nitride, silicon carbide, germanium, silicon/germanium or gallium arsenide.

78. The device of claim 74 wherein the insulation layer includes silicon nitride and the anchor material includes silicon, silicon oxide, silicon carbide, germanium, silicon/germanium or gallium arsenide.

79. The device of claim 74 wherein the second encapsulation layer includes an epitaxially deposited polycrystalline silicon.

80. The device of claim 74 further including a third encapsulation layer disposed on the second encapsulation layer to further seal the chamber.

81. The device of claim 80 wherein the third encapsulation layer is a metal material including aluminum, chromium, gold, silver, molybdenum, platinum, palladium, tungsten, titanium, silicide and/or copper.

82. The device of claim 80 wherein the third encapsulation layer is an insulating material including silicon oxide, silicon nitride, BPSG, PSG and/or SOG.

83. The device of claim 74 further including:

a contact; and

a trench, disposed around at least a portion of the contact, wherein the trench is disposed outside the chamber and wherein the trench includes an insulating material disposed therein.

84. The device of claim 83 wherein the trench surrounds a portion of the contact that is disposed outside of the chamber.

85. The device of claim 83 wherein the insulating material disposed in the trench is silicon nitride or silicon oxide.

86. A microelectromechanical device comprising:

a substrate;

an insulation layer disposed on the substrate;

a first semiconductor layer disposed on or above the insulation layer;

an anchor that is disposed in an opening in the insulation layer and the first semiconductor layer and contacts the substrate, wherein the anchor includes a material that is different from the insulation layer;

a second semiconductor layer, disposed on the anchor;

a fixed electrode, formed, in part, from the second semiconductor layer, wherein the fixed electrode is affixed to the substrate via the anchor;

a moveable electrode, formed, in part, from the second semiconductor layer, wherein the moveable electrode is disposed, at least in part, in a chamber;

a first encapsulation layer, disposed over at least a portion of the moveable electrode, wherein the first encapsulation layer is at least a portion of a wall of the chamber; and

a second encapsulation layer, deposited on the first encapsulation layer, to seal the chamber, wherein the second encapsulation layer includes a semiconductor material.

87. The device of claim 86 wherein the first encapsulation layer includes a porous semiconductor material.

88. The device of claim 87 wherein the second encapsulation layer includes polycrystalline silicon, silicon carbide, silicon/germanium, germanium, or gallium arsenide.

89. The device of claim 86 wherein the insulation layer includes silicon oxide and the anchor material includes silicon nitride, silicon carbide, germanium, silicon/germanium or gallium arsenide.

90. The device of claim 86 wherein the insulation layer includes silicon nitride and the anchor material includes silicon, silicon oxide, silicon carbide, germanium, silicon/germanium or gallium arsenide.

91. The device of claim 86 wherein a substantial portion of the fixed electrode overlying the anchor material is a monocrystalline silicon or a polycrystalline silicon.

92. The device of claim 86 wherein the second encapsulation layer is an epitaxially deposited polycrystalline silicon.

93. The device of claim 86 further including a third encapsulation layer disposed on the second encapsulation layer.

94. The device of claim 93 wherein the third encapsulation layer is a metal material including aluminum, chromium, gold, silver, molybdenum, platinum, palladium, tungsten, titanium, silicide and/or copper.

95. The device of claim 93 wherein the third encapsulation layer is an insulating material including silicon oxide, silicon nitride, BPSG, PSG and/or SOG.

96. The device of claim 86 further including:

a contact; and

a trench, disposed around at least a portion of the contact, wherein the trench is disposed outside the chamber and wherein the trench includes an insulating material disposed therein.

97. The device of claim 96 wherein the trench surrounds a portion of the contact that is disposed outside of the chamber.

98. The device of claim 96 wherein the insulating material disposed in the trench is silicon nitride or silicon oxide.