TWI497717B - High source to drain breakdown voltage vertical field effect transistors - Google Patents

Description

High field drain breakdown voltage vertical field effect transistor

The invention is a vertical field effect transistor with high source-drain breakdown voltage, comprising N+, N-, P, N- and drain N+ from the source, and N+, N- and P-type bodies of the source thereof. The body Diode, and the N+, N-, and P-type bodies from the source also form an integral diode, that is, form a back-to-back connection diode, which has a bidirectional high breakdown voltage value vertical. Field effect transistor.

FIG. 1 is a structural diagram of a conventional first power metal oxide semiconductor field effect transistor (Power MOSFET). As can be seen from the figure, the N+ of the source S is connected with the P type body to form a first 1 Body Diode (BD1), which is viewed from the drain D, has a Drain-Source Breakdown Voltage (BVds) high; and since the source S, its source-drain breakdown voltage The Source-Drain Breakdown Voltage (BVsd) has only a PN combined with a voltage drop and a low voltage drop.

2 is a structural diagram of a conventional second power metal oxide semiconductor field effect transistor (Power MOSFET). It can be seen from the figure that it is N+ type from the source S of N+, P, N- to the drain D. The breakdown voltage of the drain D to the source S is a breakdown voltage value of the second body diode BD2 and the third body diode BD3, wherein the breakdown voltage of the third body diode BD3 is high, and The second body diode BD2 is a forward voltage drop value, and the source-drain breakdown voltage value BVsd is the breakdown voltage value of the second body diode BD2 and the third body diode BD3 from the source S. The forward voltage value is known from the N+N-binding theory, and the breakdown voltage value of the N+P combined diode of the second body diode BD2 is absolutely smaller than the collapse voltage value of the N+N-P combination of the present invention.

In order to provide the need for bidirectional switching or synchronous rectification (Synchronous Rectifier): In the present invention, an N-type body is added between the source N+ and the P-type body to obtain a high source-drain breakdown voltage value.

The invention can obtain a bidirectional switching characteristic in which the source drain breakdown voltage value is equal to the drain source breakdown voltage value.

The present invention can also arbitrarily set the source-drain breakdown voltage value and the drain-source breakdown voltage value according to the requirements of the synchronous rectification function.

FIG. 3 is a structural diagram of an N-channel metal oxide semiconductor field effect transistor (N-channel MOSFET) according to the present invention. As can be seen from the figure, the source S and the N+ body are connected together, and the N+ type and the N-type are connected. The body is combined, the N-type body is combined with the P-type body to form a N+ N-P-bonded Fourth Body Diode (BD4); the drain D is connected with the N+ type body, N+ type The body is combined with the N-type body, and the N-type body is combined with the P-type body to form a N+ N-P-bonded fifth body diode (BD5); as shown in Fig. 3, the fourth The P-type body of the body diode BD4 and the P-type body of the 5th body diode BD5 are a common body, which are viewed from the source drain or drain source of FIG. 3, which are back-to-back body diodes; The Doping Concentrations of N- are determined by the demand of the breakdown voltage value, and are not self-limiting.

FIG. 4 is a structural diagram of a P-channel metal oxide semiconductor field effect transistor (P-Channel MOSFET) according to the present invention. As can be seen from the figure, the source S and the P+ body are connected together, and the P+ type and the P-type are connected. When the bodies are combined, the P-type body is combined with the N-type body to form a P+ P-N combined sixth body Diode (BD6); the drain D is connected with the P+ type body, P+ type The body is combined with the P-type body, and the P-type body is combined with the N-type body to form a P+ P-N combined seventh body diode (Seventh Body) Diode, BD7); It can be seen from Fig. 4 that the N-type body of the sixth body diode BD6 and the N type body of the seventh body diode BD7 are a common body, which is viewed from the source drain or drain source of FIG. It is a face-to-face body diode; its Doping Concentrations of P+ and P- depend on the demand of the breakdown voltage value, and are not self-limiting.

S‧‧‧ source

D‧‧‧Drain

G‧‧‧ gate

N+‧‧‧ heavily doped N-type body

N-‧‧‧Lightly doped N-type body

N‧‧‧N body

P+‧‧‧ heavily doped P type body

P-‧‧‧Lightly doped P-type body

P‧‧‧P body

BD1, BD2, BD3, BD4, BD5, BD6, BD7‧‧‧1st, 2nd, 3rd, 4th, 5th, 6th, 7th body diodes

1 is a structural diagram of a conventional first power metal oxide semiconductor field effect transistor.

2 is a structural diagram of a conventional second power metal oxide semiconductor field effect transistor.

3 is a structural diagram of an N-channel metal oxide semiconductor field effect transistor of the present invention.

4 is a structural diagram of a P-channel metal oxide semiconductor field effect transistor of the present invention.

N+‧‧‧Heady doping N type material

N-‧‧‧Light doping N type material

P‧‧‧P body

S‧‧‧ source

G‧‧‧ gate

D‧‧‧Drain

BD4‧‧‧4th body diode

BD5‧‧‧5th body diode

Claims (4)

A vertical field effect transistor with high source-drain breakdown voltage, characterized in that it comprises: a heavily doped N-type body connected to a source; a lightly doped N-type body combined with a heavily doped N-type body; A P-type body is combined with the lightly doped N-type body; the above-mentioned one heavily doped N-type body, one lightly doped N-type body and one P-type body are sequentially combined to form an integrated diode. A vertical field effect transistor according to the high source-drain breakdown voltage of claim 1 is characterized in that the vertical field effect transistor is an N-channel metal oxide semiconductor field effect transistor. A vertical field effect transistor with high source-drain breakdown voltage, characterized in that it comprises: a heavily doped P-type body connected to a source; a lightly doped P-type body combined with a heavily doped P-type body; An N-type body is combined with the lightly doped P type body; the above-mentioned one heavily doped P type body, one lightly doped P type body and one N type body are sequentially combined to form an integral diode. The vertical field effect transistor of the high source-drain breakdown voltage of claim 3 is characterized in that the vertical field effect transistor is a P-channel metal oxide semiconductor field effect transistor.