CN202373585U - Transverse power MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) device structure adopting reduced surface field (RESURFE) technology - Google Patents

The utility model discloses a transverse power MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) device structure adopting a reduced surface field (RESURFE) technology. The transverse power MOSFET device structure comprises a P-type substrate, wherein an N-well drift region, a source region and a drain region are formed on the P-type substrate; a field oxygen region is formed on the N-well drift region; the source region is connected with a source electrode through a contact hole, and the drain region is connected with a drain electrode through a contact hole; a grid polycrystal field plate is arranged on the field oxygen region; the source electrode and the drain electrode are of an interdigital structure, and the fingertip-shaped source electrode and the fingertip-shaped drain electrode are arrayed alternatively; first grid metal at one end of a device is connected with grid polycrystal through a contact hole; and second grid metal is arranged along the length direction of the fingertip structures of the source electrodes, the second grid metal and the grid polycrystal are parallel, and the second grid metal is connected with the grid polycrystal through a plurality of grid metal contact holes. According to the utility model, by means of improving an interdigital transverse power MOSFET grid, the switching uniformity of the device along the fingertip direction can be improved, the structural length of each fingertip can be increased, the allowable maximal current is increased and a safety work region of the device is improved.

Adopt the lateral direction power MOSFET device architecture that reduces the surface field technology

Technical field

The utility model relates to a kind of power MOSFET device, is specifically related to a kind of lateral direction power MOSFET device architecture that reduces the surface field technology that adopts.

Background technology

The lateral direction power MOSFET device architecture of existing withstand voltage employing Single Resurfe greater than 200V (individual layer reduction surface field) technology is as shown in Figure 1; Comprise P type substrate; Be formed with N trap drift region, source region, drain region on the P type substrate, be formed with an oxygen district on the N trap drift region; The source region connects source electrode through contact hole, and the drain region connects drain electrode through contact hole; Oxygen district, field is provided with grid polycrystalline field plate;

Also can constitute Double Resurfe (the double-deck surface field that reduces) structure, with the conducting resistance of reduction device at the surface or the middle increase P type layer that passes through of N trap drift region.

The lateral direction power MOSFET device of this structure, its source leak metal electrode except the effect that can play electric leakage position, connection source, and the surface field of metal field plate with even device leaked in the source that also can be used as, and improve the puncture voltage of device.In like manner, the grid polycrystalline partly plays control switch mosfet characteristic at active area, and oxygen on the scene district part plays even device surface electric field equally as the polycrystalline field plate, improves the effect of device electric breakdown strength.

This type of is walked crosswise, and layout design of power MOSFET is general to adopt interdigitated configuration as shown in Figure 3, and Fig. 1, Fig. 2 are along the sectional view of dotted line A among Fig. 3.Source-drain electrode adopts interdigital structure, and the source of finger tip shape is leaked alternately and arranged; Gate metal links to each other with the grid polycrystalline through contact hole at device one end.In order to improve the efficient of device, reduce the passive area of introducing by source drain terminal head, hope in the layout design that in the scope that circuit configuration allows finger tip structure length L is big as far as possible.General finger tip structure length L is between hundreds of is to several thousand microns, and total grid polycrystalline resistance, grid source electric capacity, the gate leakage capacitance of this type of device is all bigger.When device used as switch, so big grid source, gate leakage capacitance will discharge and recharge through gate resistance, postponed thereby the devices switch characteristic is introduced bigger RC (Long-distance Control).

As shown in Figure 3, gate metal only links to each other with the grid polycrystalline at device one end, because the existence of big grid polycrystalline resistance; Grid potential at the grid polycrystalline along finger tip direction skewness; Cause devices switch inhomogeneous, thereby reduce the safety operation area (SOA) of device, bring relatively poor device property.

The utility model content

The utility model technical problem to be solved provides a kind of lateral direction power MOSFET device architecture that reduces the surface field technology that adopts; It can improve because the grid voltage that grid polycrystalline resistance brings is inhomogeneous; Problems such as devices switch is inhomogeneous, and the device surface electric field is inhomogeneous.

For solving the problems of the technologies described above, the utility model adopts the technical solution of the lateral direction power MOSFET device architecture that reduces the surface field technology to be:

Comprise P type substrate, be formed with N trap drift region, source region, drain region on the P type substrate, be formed with an oxygen district on the N trap drift region; The source region connects source electrode through contact hole, and the drain region connects drain electrode through contact hole; Oxygen district, field is provided with grid polycrystalline field plate; Said source, drain electrode are interdigital structure, and the source electrode of finger tip shape is alternately arranged with drain electrode; The first grid metal links to each other with the grid polycrystalline through contact hole at device one end; It is characterized in that: the finger tip structure length direction along said source electrode is provided with the second grid metal, and said second grid metal is parallel with said grid polycrystalline, and said second grid metal links to each other with the grid polycrystalline through a plurality of grid metal contact holes.

Finger tip structure length direction along said source electrode between said second grid metal and the drain metal is provided with grid metal field plate.

A plurality of grid metal contact holes of said connection second grid metal and grid polycrystalline distribute along finger tip structure length direction, and the distance between two adjacent grid metal contact holes is not less than 100um.

The technique effect that the utility model can reach is:

The utility model can improve the switch uniformity of device along the finger tip direction through improving the grid of interdigitated lateral direction power MOSFET, increases the structure length of finger tip, increases to allow maximum current, the safety operation area (SOA) of improving device.

The utility model is through increasing the second grid metal, and evenly grid polycrystalline current potential reduces grid polycrystalline resistance, thereby makes lateral direction power MOSFET device have big safety operation area, big current capacity and moderate gate switch speed.

The utility model is through increasing the gate metal field plate, and evenly the device surface electric field improves breakdown characteristic of device.

The utility model is through introducing along the finger tip structure length direction two circle grid metal electrodes parallel with the grid polycrystalline; And choose suitable position and carry out being connected of grid metal electrode and grid polycrystalline through metal contact hole; Make lateral direction power MOSFET have big safety operation area; Big current capacity, moderate gate switch speed and uniform surface field.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is done further detailed explanation:

Fig. 1 is that prior art adopts individual layer to reduce the sketch map of the lateral direction power MOSFET device architecture of surface field technology;

Fig. 2 is that prior art adopts the double-deck sketch map that reduces the lateral direction power MOSFET device architecture of surface field technology;

Fig. 3 is the domain structure sketch map of prior art interdigitated lateral direction power MOSFET;

Fig. 4 is the sketch map that the utility model adopts the lateral direction power MOSFET device architecture that reduces the surface field technology.

Embodiment

As shown in Figure 4, the utility model adopts the lateral direction power MOSFET device architecture that reduces the surface field technology, comprises P type substrate, is formed with N trap drift region, source region, drain region on the P type substrate, is formed with an oxygen district on the N trap drift region; The source region connects source electrode through contact hole, and the drain region connects drain electrode through contact hole; Oxygen district, field is provided with grid polycrystalline field plate; Said source, drain electrode are interdigital structure, and the source electrode of finger tip shape is alternately arranged with drain electrode; The first grid metal links to each other with the grid polycrystalline through contact hole at device one end;

Length direction (being finger tip structure length L direction) along source electrode is provided with the second grid metal, and the second grid metal is parallel with the grid polycrystalline, and the second grid metal links to each other with the grid polycrystalline through a plurality of grid metal contact holes, to reduce the influence of polycrystalline resistance;

The a plurality of grid metal contact holes that connect second grid metal and grid polycrystalline distribute along finger tip structure length direction, and the distance between two adjacent grid metal contact holes is not less than 100um; Two grid metal contact holes wherein are positioned at the front end and the end of finger tip shape source electrode;

Finger tip structure length direction along said source electrode between second grid metal and the drain metal is provided with a circle grid metal field plate; Grid metal field plate is used for even device surface electric field, improves device electric breakdown strength.

The gate signal of the utility model offers the grid polycrystalline by first grid metal and second grid metal through the grid metal contact hole; Wherein the gate resistance R of grid metal contact hole junction is minimum, and the centre position of two grid metal contact holes is the maximum places of gate resistance.

When the grid metal contact hole that is connected with the grid polycrystalline when the second grid metal is made finger tip structure length direction; The influence of grid polycrystalline resistance drops to minimum; Device R C postpones minimum; If but the element layout size constancy, the grid metal contact hole of making finger tip structure length direction makes finger tip structure width W reduce.Along with reducing of source metal width, consider factors such as electromigration, source electrode maximum permissible current ability also decreases.Therefore, the utility model adopts the mode that the grid metal contact hole only in position is set, and has promptly solved the problem that the grid polycrystalline is evenly opened, and has avoided again because the problem that the current capacity that the source metal width reduces to cause descends.

Along with the increase of grid Metal Contact hole number, grid all-in resistance R effectively reduces; Because R reduces, device can evenly be opened or turn-off, and device R C postpones to reduce; Because only corresponding source metal width W can diminish in grid metal contact hole junction along finger tip structure length direction, all the other local source metal width W do not change, so device maximum permissible current ability does not have obvious decline.The utility model is taken all factors into consideration device and is evenly opened ability and big current capacity, and every at least 100um increases by place's grid metal contact hole and connects.

The second grid metal of the utility model plays the metal field plate simultaneously except the grid current potential is provided, be used for even device surface electric field, improves device electric breakdown strength.