Silicon carbide annular Schottky contact nuclear battery

[0033] Example 1

[0034] Step 1, epitaxial low-doped n-type epitaxial layer on SiC highly doped n-type substrate, such as image 3 a.

[0035] Choose a doping concentration of 5×10 18 cm -3 The SiC highly doped n-type SiC substrate is used as the substrate 6. After cleaning, the thickness is about 3μm on the epitaxial surface by low-pressure hot wall chemical vapor deposition. The doping concentration is 5×10 15 cm -3 The 4H-SiC low-doped epitaxial layer 5 has an epitaxial temperature of 1570° C., a pressure of 100 mbar, the reaction gas is silane and propane, and the carrier gas is pure hydrogen.

[0036] The second step is to form SiO on the epitaxial layer 2 Passivation layer, such as image 3 b.

[0037] At 1100±50℃, the epitaxial substrate sample is oxidized with dry oxygen for two hours to form SiO 2 Passivation layer.

[0038] The third step is to form an ohmic contact on the back of the substrate, such as image 3 c.

[0039] (3.1) Use reactive ion etching to etch a SiC layer wi

[0049] Example 2

[0050] In the first step, an epitaxial low-doped n-type epitaxial layer on a highly doped n-type SiC substrate.

[0051] Choose a doping concentration of 1×10 18 cm -3 The SiC highly doped n-type SiC substrate is used as the substrate 6. After cleaning, the thickness is about 3μm on the epitaxial surface by low-pressure hot wall chemical vapor deposition. The doping concentration is 1×10 15 cm -3 The 4H-SiC low-doped epitaxial layer 5 has an epitaxial temperature of 1570° C., a pressure of 100 mbar, the reaction gas is silane and propane, and the carrier gas is pure hydrogen.

[0052] The second step is to form SiO on the epitaxial layer 2 Passivation layer.

[0053] At 1100±50℃, the epitaxial substrate sample is oxidized with dry oxygen for two hours to form SiO 2 Passivation layer.

[0054] In the third step, an ohmic contact is formed on the back of the substrate.

[0055] (3.1) Use reactive ion etching to etch a SiC layer with a thickness of 0.5 μm on the back of the

[0065] Example 3

[0066] Step A, an epitaxial low-doped n-type epitaxial layer on a highly doped n-type SiC substrate.

[0067] Choose a doping concentration of 5×10 17 Cm -3 The SiC highly doped n-type SiC substrate is used as the substrate 6. After cleaning, the thickness is about 3μm on the epitaxial surface by low-pressure hot-wall chemical vapor deposition. The doping concentration is 5×10 14 cm -3 The 4H-SiC low-doped epitaxial layer 5 has an epitaxial temperature of 1570° C., a pressure of 100 mbar, the reaction gas is silane and propane, and the carrier gas is pure hydrogen.

[0068] Step B, SiO is formed on the epitaxial layer 2 Passivation layer.

[0069] At 1100±50℃, the epitaxial sample is oxidized with dry oxygen for two hours to form SiO 2 Passivation layer.

[0070] In step C, an ohmic contact is formed on the back of the substrate.

[0071] (C1) Use reactive ion etching to etch a SiC layer with a thickness of 0.5 μm on the back of the substrate 6;

[0072] (C2) Use electron