CN101452967A - Schottky barrier diode device and manufacturing method thereof - Google Patents

Abstract

The invention discloses a schottky barrier diode device. An anode active region on an N<-> well comprises an annular silicon groove; the silicon groove is filled with polysilicon; the polysilicon and the N<-> well are isolated with a gate oxide layer; the upper parts of two outer sides of the groove are both provided with a P-type impurity heavily doped region; and the anode active region and a cathode active region are both covered with a metal silicide layer. The invention also discloses a method for manufacturing the schottky barrier diode device. The method comprises the steps of manufacturing an isolation region on the N<-> well, etching the annular silicon groove, growing the gate oxide layer and depositing the polysilicon in turn and performing etching, doping the P-type impurity heavily doped region and the cathode active region, and depositing the metal silicide layers above the anode active region and the cathode active region. The method has simple process steps, accurately controls the contact area with metal silicide by doping P-type impurities beyond a schottky contact region, raises the reverse breakdown voltage of schottky diode, and reduces electric leakage.

Description

Schottky barrier diode device and preparation method thereof

Technical field

The present invention relates to a kind of semiconductor device, especially a kind of Schottky barrier diode device.The invention still further relates to a kind of manufacture method of semiconductor device, especially a kind of manufacture method of Schottky barrier diode.

Background technology

Schottky diode device is mainly used in high speed rectification field.The structure of existing Schottky diode is essentially metal alloy layers such as Ti/W and extends to N type epitaxial loayer by forming behind suitable alloy temperature, this device performance is stable, can reduce saturation voltage drop effectively and improve switching speed, but this device making technics complexity is incompatible with common CMOS technology.The reverse breakdown voltage of Schottky tube is low simultaneously, and electric leakage greatly also is a urgent problem.

Summary of the invention

Technical problem to be solved by this invention provides a kind of Schottky barrier diode device, and a kind of manufacture method of Schottky barrier diode device, can pass through simple process steps, accurately control Schottky contacts zone area, reduce the electric leakage of Schottky barrier diode, the reverse breakdown voltage of raising.

For solving the problems of the technologies described above, the technical scheme of Schottky barrier diode device of the present invention is, at N ^-Include anodal active area, cathode active region and isolated area on the trap, described isolated area separates described anodal active area and cathode active region, comprise annular silicon trench in the described anodal active area, be filled with polysilicon in the described silicon trench, isolate between described polysilicon and the described N trap gate oxide is arranged, described groove two outer upper all have the p type impurity heavily doped region, described cathode active region is a N type impurity heavily doped region, and described anodal active area and cathode active region top all are coated with metal silicide layer.

The technical scheme of the manufacture method of Schottky barrier diode of the present invention is to comprise the steps:

(1) at N ^-Make isolated area on the trap;

(2) etch annular silicon trench;

(3) grow successively gate oxide and deposit polysilicon;

(4) polysilicon beyond the silicon trench is carried out etching, then p type impurity heavily doped region and cathode active region are mixed;

(5) metal silicide layer of anodal active area of deposit and cathode active region top.

The present invention utilizes existing CMOS technology, has realized metal silicide and N ^-Direct contact between trap, outside the Schottky contacts zone, etch a circle groove, in groove, grow gate oxide, deposit polysilicon and metal silicide, thereby formation Schottky barrier diode, its processing step is simple, by the contact area at accurate control of the overseas doping p type impurity of Schottky contact region and metal silicide, the reverse breakdown voltage that improves Schottky tube is low, reduces electric leakage.

Description of drawings

The present invention is further detailed explanation below in conjunction with drawings and Examples:

Fig. 1 is the cross-sectional view of Schottky barrier diode device of the present invention;

Fig. 2～Fig. 5 is the schematic diagram of each step of Schottky barrier diode device manufacture method of the present invention;

Fig. 6 is the schematic top plan view of Schottky barrier diode device of the present invention.

Embodiment

The invention provides a kind of Schottky barrier diode device, as shown in Figure 1, at N ^-Include anodal active area, cathode active region and isolated area on the trap, described isolated area Field separates described anodal active area and cathode active region, comprise annular silicon trench in the described anodal active area, be filled with polysilicon in the described silicon trench, described polysilicon and described N ^-Isolating between the trap has gate oxide, and described groove two outer upper all have the p type impurity heavily doped region, as P among Fig. 1 ⁺Shown in the zone, described cathode active region is a N type impurity heavily doped region, as N among Fig. 1 ⁺Shown in the zone, described anodal active area and cathode active region top all are coated with metal silicide layer.

The present invention also provides a kind of manufacture method of above-mentioned Schottky barrier diode device, comprises the steps:

(1) at N ^-Make isolated area on the trap;

(2) etch annular silicon trench, as shown in Figure 2;

(3) grow successively gate oxide and deposit polysilicon;

(4) polysilicon beyond the silicon trench is carried out etching, then p type impurity heavily doped region and cathode active region are mixed, as shown in Figure 3;

(5) metal silicide layer of anodal active area of deposit and cathode active region top, as shown in Figure 4.

Carry out subsequent technique at last, make the parts such as contact electrode of Schottky barrier diode device, thereby finish the device architecture of Schottky barrier diode as shown in Figure 5.

Schottky barrier diode device of the present invention and preparation method thereof also can carry out etching to active area etch areas among Fig. 6 in conjunction with shown in Figure 6, has just obtained annular silicon trench.Anodal active area is provided with anode electrode, and cathode active region is provided with negative electrode.Cathode active region is enclosed within outside the anodal active area, and the centre is separated with isolated area Field.Among Fig. 6, in the lines NP institute area surrounded, carry out the doping of N type impurity, become N type impurity heavily doped region; In the lines PP institute area surrounded, carry out p type impurity and mix, become the p type impurity heavily doped region.

The present invention utilizes existing CMOS technology, realizes metal of alloying and N by metal silicide layer ^-Direct contact between trap etches a circle groove outside the Schottky contacts zone, utilization forms the method for metal-oxide-semiconductor area of grid, in groove, grow gate oxide, deposit polysilicon and metal silicide, thus form a kind of Schottky barrier diode; Simultaneously by accurately controlling contact area at the overseas doping p type impurity of Schottky contact region, during reverse operation, near the N the annular silicon trench ^-Well area produces the electric field that points to polysilicon, can effectively decompose by N ^-Trap points to the electric field of metal silicide layer, has improved puncture voltage with this, has reduced electric leakage.

Claims (2)

1. a Schottky barrier diode device is characterized in that, at N ^-Include anodal active area, cathode active region and isolated area on the trap, described isolated area separates described anodal active area and cathode active region, comprises annular silicon trench in the described anodal active area, is filled with polysilicon in the described silicon trench, described polysilicon and described N ^-Isolating between the trap has gate oxide, and described groove two outer upper all have the p type impurity heavily doped region, and described cathode active region is a N type impurity heavily doped region, and described anodal active area and cathode active region top all are coated with metal silicide layer.

2. the manufacture method of a Schottky barrier diode device as claimed in claim 1 is characterized in that, comprises the steps:

(1) at N ^-Make isolated area on the trap;

(2) etch annular silicon trench;

(3) grow successively gate oxide and deposit polysilicon;

(4) polysilicon beyond the silicon trench is carried out etching, then p type impurity heavily doped region and cathode active region are mixed;

(5) metal silicide layer of anodal active area of deposit and cathode active region top.

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