A Trench Schottky Diode
A Schottky diode and trench type technology, applied in semiconductor devices, electrical components, circuits, etc., to achieve high reverse breakdown voltage, improve current capability, and increase effective area
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Embodiment 1
[0015] Such as figure 1 As shown, a trench type Schottky diode in this example includes a metallized cathode 1, a first conductivity type semiconductor substrate 2, a drift region 3 and a metallized anode 10 that are sequentially stacked from bottom to top; The drift region 3 includes a first deep trench 4 and a second deep trench 5, the second deep trench 5 is located between the first deep trenches 4 on both sides; the second deep trench 5 is filled with polysilicon 7, the There is a thin oxide layer 63 between the polysilicon 7 and the sidewall of the second deep trench 5, and a first thick oxide layer 62 is formed between the polysilicon 7 and the bottom of the thin oxide layer 63. The polysilicon 7 is connected to the metallized anode 10 and the thin oxide layer. 63 is in contact with the first thick oxide layer 62; the lower end of the first deep groove 4 has a second thick oxide layer 61, and the first deep groove 4 is also filled with Schottky metal 9, the Schottky met...
Embodiment 2
[0021] In this example, on the basis of the first embodiment, the depths of the deep grooves 4 and 5 are increased, so that the thick oxide layers 61 and 62 are connected to the substrate 2 . The beneficial effect of this example is that the effective area of the Schottky junction can be further increased, while the reverse withstand voltage can be improved and the reverse leakage current can be reduced.
Embodiment 3
[0023] In this example, on the basis of Example 1, the thick oxide layer 61 at the bottom of the deep trench 4 is replaced with the buried semiconductor layer 11 of the second conductivity type. The beneficial effect of this example is that it can further prevent electric field concentration at the bottom corner of the deep groove and improve the reverse withstand voltage.
[0024] Taking Example 1 as an example, the structure of the present invention can be prepared by the following method, and the process steps are:
[0025] (1) Monocrystalline silicon preparation and epitaxial growth: such as Figure 4 , on the heavily doped single crystal silicon substrate 2 with the first conductivity type, an epitaxial layer with a certain thickness and doping concentration and the same conductivity type (that is, the drift region 3) is grown by a method such as vapor phase epitaxy (VPE);
[0026] (2) Etching deep grooves: such as Figure 5 Depositing a hard mask 12 (such as silicon ni...
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