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US 10,896,981 B1Granted
Integration of vertical GaN varactor with HEMT
AssigneeQUALCOMM Incorporated
InventorsGengming Tao, Xia Li, Bin Yang
Life of this patent
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Abstract
Aspects generally relate to a P-N junction varactor that can be integrated with high electron mobility transistor (HEMT) in a single device or die. The varactor and HEMT are fabricated with the same materials forming various layers of the varactor and HEMT. Using the same material stack-up to form the varactor and HEMT can reduce the number of processing steps during the fabrication of the integrated varactor and HEMT device. The integrated varactor and HEMT device may be used for RF circuits, such as radio frequency front end (RFFE) devices for use in 5G.
Claims25
An integrated circuit comprising:
- a substrate;
- a buffer layer on the substrate;
- a varactor on a first portion of the buffer layer, the varactor comprising:
- a first gallium nitride (GaN) layer doped with a P-type dopant (P+ GaN layer) on the first portion of the buffer layer;
- a first stack of layers on the first P+ GaN layer, the first stack of layers comprising:
- a first varactor layer comprising a first material comprising a GaN compound, the first material doped to a first concentration of N-type dopant;
- and
- a second varactor layer comprising a second material comprising a GaN compound, the second material doped to a second concentration of the N-type dopant;
- a first contact coupled to a portion of the first P+ GaN layer, the first contact electrically isolated from the first stack of layers;
- and
- a second contact coupled to the second varactor layer;
- and
- a high electron mobility transistor (HEMT) comprising:
- a second P+ GaN layer on a second portion of the buffer layer electrically isolated from the first P+ GaN layer;
- a second stack of layers on the second P+ GaN layer, the second stack of layers comprising:
- a first HEMT layer comprising the first material doped to the first concentration of the N-type dopant;
- and
- a second HEMT layer comprising the second material doped to the second concentration of the N-type dopant;
- a third contact coupled to a first portion of the second HEMT layer;
- a fourth contact coupled to a second portion of the second HEMT layer;
- and
- a fifth contact coupled to a third portion of the second HEMT layer, the fourth contact located between the third and fifth contacts, the third, fourth, and fifth contacts electrically isolated from each other.
19 more elements
An integrated circuit comprising:
- a varactor comprising;
- a P+ GaN layer;
- a N− GaN layer on the P+ GaN layer;
- a N− AlGaN layer on the P+ GaN layer;
- a first contact coupled to the P+ GaN layer;
- and
- a second contact coupled to the N− AlGaN layer;
- and
- a high electron mobility transistor (HEMT) comprising;
- a P+ GaN layer coplanar with the P+ GaN layer of the varactor;
- an N− GaN layer on the P+ GaN layer, the N− GaN layer coplanar with the N− GaN layer of the varactor;
- a N− AlGaN layer on the P+ GaN layer, the N− AlGaN layer coplanar with the N− AlGaN layer of the varactor;
- and
- a third contact, a fourth contact, and a fifth contact coupled to the N− AlGaN layer, the third, fourth, and fifth contacts electrically isolated from each other and the fourth contact between the third and fifth contacts.
11 more elements
A radio frequency (RF) module comprising:
- a single die comprising a substrate;
- a buffer layer on the substrate;
- a varactor on a first portion of the buffer layer, the varactor comprising:
- a first gallium nitride (GaN) layer doped with a P-type dopant (P+ GaN layer) on the first portion of the buffer layer;
- and
- a first stack of layers on the first P+ GaN layer, the first stack of layers comprising:
- a first varactor layer comprising a first material comprising a GaN compound, the first material doped to a first concentration of N-type dopant;
- and
- a second varactor layer comprising a second material comprising a GaN compound, the second material doped to a second concentration of the N-type dopant;
- a first contact coupled to a portion of the first P+ GaN layer, the first contact electrically isolated from the first stack of layers;
- and
- a second contact coupled to the second varactor layer;
- and
- a high electron mobility transistor (HEMT) comprising:
- a second P+ GaN layer on a second portion of the buffer layer;
- and
- a second stack of layers on the second P+ GaN layer, the second stack of layers comprising:
- a first HEMT layer comprising the first material doped to the first concentration of the N-type dopant;
- and
- a second HEMT layer comprising the second material doped to the second concentration of the N-type dopant;
- a third contact coupled to a first portion of the second HEMT layer;
- a fourth contact coupled to a second portion of the second HEMT layer;
- and
- a fifth contact coupled to a third portion of the second HEMT layer, the fourth contact located between the third and fifth contacts, the third, fourth, and fifth contacts electrically isolated from each other,
- wherein:
- the HEMT is configured to receive an RF signal and output an amplified RF signal;
- and
- the varactor is configured to couple the amplified RF signal to a load.
25 more elements
A method of manufacturing a device with a varactor integrated with a high electron mobility transistor (HEMT), the method comprising:
- forming a substrate;
- forming a buffer layer on the substrate;
- forming a first P+ GaN layer on a first portion of the buffer layer and forming a second P+ GaN layer on a second portion of the buffer layer, the first P+ GaN layer electrically isolated from the second P+ GaN layer;
- forming a first N− GaN layer on a portion of the first P+ GaN layer and forming a second N− GaN layer on the second P+ GaN layer, the first N− GaN layer electrically isolated from the second N− GaN layer;
- forming a first N− AlGaN layer on the first N− GaN layer and forming a second N− AlGaN layer on the second N− GaN layer, the first N− AlGaN layer electrically isolated from the second N− AlGaN layer;
- and
- forming a first contact coupled to a portion of the first P+ GaN layer, the first contact electrically isolated from the first N− GaN layer, forming a second contact coupled to the first N− AlGaN layer, forming a third contact coupled to a first portion of the second N− AlGaN layer, forming a fourth contact coupled to a second portion of the second N− AlGaN layer, and forming a fifth contact coupled to a third portion of the second N− AlGaN layer, the fourth contact located between the third and fifth contacts, the third, fourth, and fifth contacts electrically isolated from each other.
4 more elements
A method of manufacturing a device with a varactor integrated with a high electron mobility transistor (HEMT), the method comprising:
- forming a substrate;
- forming a buffer layer on the substrate;
- forming a P+ GaN layer on the buffer layer;
- forming an N− GaN layer, having a non-uniform doping profile, on a portion of the P+ GaN layer;
- forming an N− AlGaN layer on the N− GaN layer;
- and
- forming a first contact coupled to a portion of the P+ GaN layer, the first contact electrically isolated from the N− GaN layer, forming a second contact coupled to a first portion of the N− AlGaN layer, forming a third contact coupled to a second portion of the N− AlGaN layer, and forming a fourth contact coupled to a third portion of the N− AlGaN layer, the fourth contact located between the second and third contacts, the second, third, and fourth contacts electrically isolated from each other.
4 more elements
Dependencies are inferred from the claim text.