Gallium nitride (GaN) transistor structures on a substrate

Patent metadata

Field	Value
Publication number	US-11195944-B2
Application number	US-201515576508-A
Country	US
Kind code	B2
Filing date	Jun 26, 2015
Priority date	Jun 26, 2015
Publication date	Dec 7, 2021
Grant date	Dec 7, 2021

Abstract

Techniques are disclosed for gallium nitride (GaN) oxide isolation and formation of GaN transistor structures on a substrate. In some cases, the GaN transistor structures can be used for system-on-chip integration of high-voltage GaN front-end radio frequency (RF) switches on a bulk silicon substrate. The techniques can include, for example, forming multiple fins in a substrate, depositing the GaN layer on the fins, oxidizing at least a portion of each fin in a gap below the GaN layer, and forming one or more transistors on and/or from the GaN layer. In some cases, the GaN layer is a plurality of GaN islands, each island corresponding to a given fin. The techniques can be used to form various non-planar isolated GaN transistor architectures having a relatively small form factor, low on-state resistance, and low off-state leakage, in some cases.

First claim

What is claimed is:

1. An integrated circuit comprising:
a bulk substrate including semiconductor material;
a plurality of fins native to the bulk substrate, wherein at least one of the fins includes an oxidized portion and an unoxidized portion above the oxidized portion;
a structure including gallium and nitrogen, the structure directly on at least some of the fins and above the oxidized portion of the at least one fin; and
a transistor having a gate stack on the structure, such that the gate stack overlaps the structure in a plan view.

2. The integrated circuit of claim 1 , wherein the bulk substrate is one of a silicon bulk substrate, a silicon germanium bulk substrate, or a germanium bulk substrate.

3. The integrated circuit of claim 1 , wherein the structure includes a first layer and a second layer, the first layer including gallium and nitrogen, and the second layer is at least partially between some of the fins and the first layer, wherein the second layer includes aluminum and nitrogen.

4. The integrated circuit of claim 1 , wherein the structure includes a first layer and a second layer, the first layer including gallium and nitrogen, and the second layer at least partially between some of the fins and the first layer, wherein the second layer includes gallium and nitrogen.

5. The integrated circuit of claim 4 , wherein the transistor includes the second layer.

6. The integrated circuit of claim 5 , further comprising an aluminum-including layer above the second layer.

7. The integrated circuit of claim 1 , wherein the structure includes a first layer and a second layer, the first layer including gallium and nitrogen, and the second layer is a graded layer above the first layer, the graded layer including a change in content of at least one material.

8. The integrated circuit of claim 7 , wherein the graded layer includes gallium, nitrogen, and indium.

9. The integrated circuit of claim 7 , further comprising an additional layer above the graded layer, the additional layer including aluminum and nitrogen.

10. The integrated circuit of claim 1 , further comprising a source region and a drain region, the source and drain regions including gallium and nitrogen, the source and drain regions further including an n-type dopant.

11. The integrated circuit of claim 1 , wherein the transistor is electrically isolated from the substrate by way of the oxidized portion of the at least one fin.

12. The integrated circuit of claim 1 , wherein the transistor includes at least one of: a planar configuration, a non-planar configuration, a finned configuration, a tri-gate configuration, a nanowire configuration, a gate-all-around configuration, high-electron-mobility transistor (HEMT) architecture, pseudomorphic HEMT (pHEMT) architecture, two-dimensional electron gas (2DEG) architecture, three-dimensional electron gas (3DEG) architecture, three-dimensional polarization field-effect transistor (FET) architecture, multiple quantum-well (MQW) architecture, an enhancement mode configuration, or super-lattice architecture.

13. A system-on-chip including a radio frequency (RF) switch, the RF switch comprising the integrated circuit of claim 1 .

14. A computing system comprising the integrated circuit of claim 1 .

15. An integrated circuit comprising:
a layer including gallium and nitrogen, the layer over one or more fins, each of the one or more fins native to a subjacent bulk silicon (Si) substrate and including an oxidized portion and an unoxidized portion above the oxidized portion, such that the layer is electrically isolated from the Si substrate by the corresponding oxidized portion; and
a gate stack over a portion of the layer.

16. The integrated circuit of claim 15 , further comprising an additional layer at least partially between at least one of the one or more fins and the layer, wherein the additional layer includes aluminum and nitrogen.

17. The integrated circuit of claim 15 , wherein the layer and the gate stack are part of a transistor that includes at least one of: a planar configuration, a non-planar configuration, a finned configuration, a tri-gate configuration, a nanowire configuration, a gate-all-around configuration, high-electron-mobility transistor (HEMT) architecture, pseudomorphic HEMT (pHEMT) architecture, two-dimensional electron gas (2DEG) architecture, three-dimensional electron gas (3DEG) architecture, three-dimensional polarization field-effect transistor (FET) architecture, multiple quantum-well (MQW) architecture, an enhancement mode configuration, or super-lattice architecture.

18. The integrated circuit of claim 15 , wherein the layer is over at least a portion of the sidewalls of the one or more fins and on a top surface of the one or more fins.

19. An integrated circuit including at least one transistor, the integrated circuit comprising:
a bulk silicon substrate;
first and second fins native to the substrate, wherein each of the first and second fins includes an oxidized portion and an unoxidized portion above the oxidized portion; and
a layer including gallium and nitrogen, the layer over at least a portion of the sides of the first fin and over a top surface of the second fin, wherein the oxidized portion of each of the first and second fins is between the layer and the substrate.

Assignees

• Intel Corp

Inventors

• Then Han Wui
• Dasgupta Sansaptak
• Gardner Sanaz K
• Radosavljevic Marko
• Sung Seung Hoon
• Chau Robert S

Classifications

• H10W10/181

  Semiconductor-on-insulator [SOI] isolation regions, e.g. buried oxide regions of SOI wafers · CPC title

• H10P90/1912

  using selective deposition, e.g. epitaxial lateral overgrowth [ELO] or selective deposition of single crystal silicon · CPC title

• H10D30/62

  Fin field-effect transistors [FinFET] · CPC title

• H10D30/43

  having one-dimensional [1D] charge carrier gas channels, e.g. quantum wire FETs or transistors having 1D quantum-confined channels · CPC title

• H10D30/475 Primary

  having wider bandgap layer formed on top of lower bandgap active layer, e.g. undoped barrier HEMTs such as i-AlGaN/GaN HEMTs · CPC title