Precaution for use～MOSFET～
１．About structure of the MOSFET and quality improvement
The equivalent circuit of the MOSFET generally becomes like figure 1 and shows it to our datasheet.
It is explained all parts as follows.
MOSFET(1) MOSFETDrain

We develop MOSFET of the trench structurethat is available for the miniaturization of theGatepattern.
A cross section is shown in figure 2.
A trench is formed in the silicon surface withthe trench structure to show it in figure 2.

Parasitic Diode

Protective DiodeSource

Fig. 1

And the sidewall of the trench is used as a

MOSFET equivalent circuit（For Nch MOSFET）

channel.
This miniaturization of the pattern is possible
with this structure and can realize low ON
resistance at the chip size that is smaller
than a case of the conventional DMOSstructure.
In addition, barrier metal is spread with thealuminum wiring of the Source electrode, andquality reliability improves.
Fig. 2

Cross section of trench structure（For Nch MOSFET）(2) Protection diode of the Gate
The protection diode is formed for ESD protection use of the Gate electrode of the MOSFET.
VGSS is decided by the breakdown voltage of this protection diode.
Because this protection diode is aimed for ESD protection use in case of the handling of theMOSFET, in the serge absorption use with the actual machine, we recommend that Zener
diodes are used by attaching externally.
In addition, we develop the product which added resistance to the Gate to improve ability for
ESD protection. Please talk about the details with our sales office.
(3) Parasitic diodeIt is a diode formed between Drain to Source structurally of the MOSFET. Therefore, it does nottake reverse voltage between Drain to Source.
As for this diode, it is not intended to apply an electric current to the forward direction.
When a diode is necessary, we recommend that an external diode is used on a circuit.

© ISAHAYA ELECTRONICS CORPORATION

1

Precaution for use～MOSFET～
2．About the drive voltage of the MOSFETThe drive voltage of the MOSFET is the smallest voltage that can flow rating Drain current ID.
Therefore, the use in lower voltage than the specified drive voltage is enabled when Drain
current to apply on the circuit is small.
About this matter, we explain a case of INK0010AC1 as an example.
We show ID-VGS characteristic of INK0010AC1 in figure 3.
The rating of the ID of INK0010AC1 is 260mA, but, in the case of VGS=3V, ID=100mA is
acceptable, and, in the case of VGS=2.5V, ID = 10mA is acceptable.
About other kinds, the drive voltage changes by Drain current used likewise, too. If you haveany questions, please talk with our sales office.

INK0010AC1 ID -VGS
INK0010AC1 ID－VGS
1000

Ta=25℃
VDS=10V

Drain current
ID (mA)
ドレイン電流ID (mA)

260mA10010101Fig. 3© ISAHAYA ELECTRONICS CORPORATION

234Gate-Sourcevoltage VGSV(V)ドレイン-ソース間電圧GS (V)

5ID-VGS characteristic of INK0010AC12

Precaution for use～MOSFET～
3．About Zener diode built in MOSFET(1) Avalanche failure

VCC

VCC

Avalanche failure may occur when MOSFET breaks
down due to a surge voltage, which is generated when
the switching operation under an inductive load, exceeds
Drain-Source breakdown voltage VDSS of the MOSFET.
A parasitic element (bipolar transistor /Tr, resistance /R,負Load荷MCUcondenser /C) such as figure 5 is formed in MOSFET
structurally.
On the avalanche operation, an electric current showing
in figure 5 in a dashed line will flow through parasiticFig. 4

capacity C, and, transistor/Tr turns on in a case beyond

Drive circuit of the inductive load
Avalanche Current

the base emitter voltage of Tr the voltage of both ends ofDrain

resistance R.
At this time, MOSFET is destroyed by an excessiveGateelectric current flowing in Tr.

CThis phenomenon is avalanche failure.

TrR(2) Method to improve avalanche breakdown capability

SourceIt is necessary to interfere with working in parasitic

Parasitic Elementtransistor /Tr which mentioned above to improve

Fig. 5 In case of conventional MOSFET

avalanche breakdown capability.
A method to reduce parasitic resistance /R in the case of conventional DMOS structure as thesemeasures is performed. As an example, the sectional structure of the conventional DMOS
product is shown in figure 6. Parasitic resistance /R becomes small to show it in the figure bydeepening the P-Body region.
The miniaturization of the pattern is necessary to reduce ON resistance of the MOSFET.
Therefore MOSFET of the trench structure that is available for miniaturization becomesmainstream now.
Because it is hard to take measures such as the DMOS structure that we mentioned above inthe case of trench structure, different measures are necessary.
Source electrodeSource electrode
Gate electrode

NNNPP

PN
Gate
P electrodeGate
electrodeNP（P-Body）
NN

Drain electrodeFig. 6

Cross section of DMOS structure

in case of Nch MOSFET© ISAHAYA ELECTRONICS CORPORATION

Drain electrodeFig. 7Cross section of Trench structure

in case of Nch MOSFET3

Precaution for use～MOSFET～(3) Development of the Ze diode built in MOSFET

Avalanche Current

Show in figure 8, we attach Zener diode witch

Drain

breaks down with the voltage that is lower than
VDSS between Drain to Source of the MOSFET toC

Gate

improve avalanche breakdown capability.

TrIn this case an electric current flows throughZener DiodeR

Zener diode before an electric current flows in aparasitic element on the avalanche operation.

SourceTherefore, parasitic transistor Tr is hard to beParasitic Element

turned on.
This Zener diode is constructed in a silicon chipFig. 8 Zener Diode built-in Nch MOSFET

same as MOSFET. Therefore, the assembling tothe small package of 3 pins is possible.
Source electrode

NPN
Gate
P electrode

Gateelectrode

NP

P

NN
Drain electrodeFig. 9Cross section of Zener Diode built-in Nch MOSFET(4) Lineup of the Ze diode built in MOSFET
Now, the development of the following two types has been completed and mass production is inprogress.
When there is a request, about the product of the standard except this, we examine
development.
VDSS(V)

VGSS(V)

ID(A)

Vth(V)

Ron(Ω)

Package

INKE111AC150±10±200.5

1.0~2.00.6

SC-59

INKE211AC150±10±201.0

1.0~2.00.3

SC-59

Please refer to our sales office for the demand of the sample.

© ISAHAYA ELECTRONICS CORPORATION4