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Semiconductor device

A semiconductor and device technology, applied in the field of semiconductor devices, can solve problems such as high on-resistance, difficulty in activating p-GaN high-concentration acceptors, and inability to achieve high electron mobility

Active Publication Date: 2013-03-13
FUJITSU LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, it is difficult to activate a high concentration of acceptors in the p-GaN layer
Furthermore, using a simple GaN intrinsic (bulk) layer as an electron transport layer (drift layer) cannot achieve high electron mobility, unlike two-dimensional electron gas (2DEG) in high electron mobility transistors (HEMTs)
This results in a high on-resistance
[0007] An example of a vertical GaN-FET with a normally-off structure without the use of a p-GaN layer has a GaN / AlGaN heterojunction barrier, which has difficulty in activating a high concentration of acceptors
[0008] However, even with the GaN / AlGaN heterojunction barrier, the use of GaN intrinsic layer as electron transport layer still increases the on-resistance

Method used

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  • Semiconductor device
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Examples

Experimental program
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Effect test

no. 1 approach

[0028] Semiconductor device

[0029] will refer to figure 1 A semiconductor device according to the first embodiment will be described. The semiconductor device includes on a substrate 10: an electron transport layer 11 formed of an i-GaN layer; an electron supply layer 12 formed of an AlGaN layer; a barrier forming layer 13 formed of an i-GaN layer; and an n-GaN layer forming the upper channel layer 14 .

[0030] GaN has a bandgap of 3.4eV. Upper channel layer 14 , barrier forming layer 13 and electron supply layer 12 are partially removed to form side surface 17 . An insulating film 20 serving as a gate insulating film is provided on the processed surface of the electron supply layer 12 , the side surface 17 , and the processed surface of the upper channel layer 14 .

[0031] A gate electrode 21 is provided on the insulating film 20 . The upper channel layer 14 is connected to the source electrode 22 . The electron supply layer 12 is connected to the drain electrode 23...

no. 2 approach

[0063] Semiconductor device

[0064] will refer to image 3 A semiconductor device according to a second embodiment will be described. The semiconductor includes: an electron transport layer 111 formed of an i-GaN layer on a substrate 110, an electron supply layer 112 formed of an AlGaN layer, an upper electron transport layer 113 formed of an i-GaN layer, and an upper electron transport layer 113 formed of an AlGaN layer. A supply layer 114 and a cap layer 115 formed of a GaN layer. GaN has a bandgap of 3.4eV. Capping layer 115 , upper electron supply layer 114 , upper electron transport layer 113 , and electron supply layer 112 are partially removed to form side surface 117 . An insulating film 120 serving as a gate insulating film is provided on the capping layer 115 , the side surface 117 , and the processed surface of the electron supply layer 112 . Gate electrode 121 is provided on insulating film 120 over electron supply layer 112 and side surface 117 . The source ...

no. 3 approach

[0099] A third embodiment will be described below. The semiconductor device according to the present embodiment has the same structure as that of the semiconductor device according to the second embodiment except that the side surface 117 is substantially vertical. The following will refer to Figure 6 A semiconductor device according to the present embodiment will be described.

[0100] In the semiconductor device according to the present embodiment, capping layer 115, upper electron supply layer 114, upper electron transport layer 113, and electron supply layer 112 are etched substantially perpendicular to substrate 110 to form steep side surfaces 117a. The steep side surface 117a may be formed by optimizing conditions for dry etching such as RIE.

[0101] It is known that the sloped side surfaces as in the second embodiment hold positive fixed charges, but the steep side surfaces as in the present embodiment hold little charges. Therefore, the formation of the steep side...

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Abstract

A semiconductor device includes: an electron-transit layer made of a semiconductor, the electron-transit layer having a first band gap; an electron-supply layer disposed on the electron-transit layer, the electron-supply layer being made of a semiconductor having a second band gap that is wider than the first band gap; a barrier-forming layer disposed on the electron-supply layer, the barrier-forming layer being made of a semiconductor having a third band gap that is narrower than the second band gap; an upper-channel layer disposed on the barrier-forming layer, the upper-channel layer being made of a semiconductor doped with an impurity; a side-surface of the barrier-forming layer and the upper-channel layer formed by partly removing the barrier-forming layer and the upper-channel layer; an insulating-film disposed on the side-surface; a gate-electrode disposed on the insulating-film; a source-electrode connected to the upper-channel layer; and a drain-electrode connected to the electron-supply layer or the electron-transit layer.

Description

technical field [0001] Embodiments discussed herein relate to semiconductor devices. Background technique [0002] One known energy efficient high voltage semiconductor device is a power transistor comprising a wide bandgap semiconductor. An example of the wide bandgap semiconductor is GaN. GaN has a band gap of 3.4 eV, which is higher than that of Si (1.2 eV) and GaAs (1.4 eV), which are common semiconductor materials. [0003] A power transistor including GaN, a wide bandgap semiconductor, has a high breakdown voltage, which enables reduction of the distance between electrodes and on-resistance. Transistors with reduced on-resistance generate less heat and are energy-efficient devices. [0004] Existing power devices include Si as a main semiconductor material. Specific examples of these power devices include power transistors, insulated gate bipolar transistors (IGBTs), and superjunction metal oxide semiconductor field effect transistors (MOSFETs), each of which inclu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L29/78H01L29/20H01L29/06
CPCH01L29/0657H01L29/4236H01L29/2003H01L29/7786H01L29/7783H01L29/7781H01L29/0847H01L2224/48091H01L2224/48247H01L2224/48257H01L2224/48472H01L2224/4903H01L2924/13091H01L2924/13055H01L2924/1305H01L2924/00014H01L2924/00H01L21/18H01L29/778
Inventor 常信和清
Owner FUJITSU LTD