Silicon carbide and related wide-bandgap transistors on semi-insulating epitaxy for high-speed, high-power applications
View Patent ↗A silicon carbide semi-insulating epitaxy layer is used to create power devices and integrated circuits having significant performance advantages over conventional devices. A silicon carbide semi-insulating layer is formed on a substrate, such as a conducting substrate, and one or more semiconducting devices are formed on the silicon carbide semi-insulating layer. The silicon carbide semi-insulating layer, which includes, for example, 4H or 6H silicon carbide, is formed using a compensating material, the compensating material being selected depending on preferred characteristics for the semi-insulating layer. The compensating material includes, for example, boron, vanadium, chromium, or germanium. Use of a silicon carbide semi-insulating layer provides insulating advantages and improved thermal performance for high power and high frequency semiconductor applications.
1. A method for forming a microelectronic device, comprising:
forming a semi-insulating silicon carbide layer on a substrate wherein the silicon carbide layer is formed by supplying a transition metal from a solid source selected from the group consisting of vanadium carbide and vanadium nitride; and
forming a first semiconductor device on the semi-insulating silicon carbide layer.
2. The method of claim 1 , wherein the substrate is a conductor.
3. The method of claim 2 , wherein the semi-insulating silicon carbide layer is formed epitaxially.
4. The method of claim 1 , wherein the semi-insulating silicon carbide layer comprises boron.
5. The method of claim 1 , wherein the semi-insulating silicon carbide layer comprises a transition metal.
6. The method of claim 1 , wherein the semi-insulating silicon carbide is formed using site competition epitaxy.
7. The method of claim 1 , wherein forming a semi-insulating silicon carbide layer comprises:
providing a source of silicon;
providing a source of carbon; and
varying a relative concentration of the silicon to the carbon, such that site competition epitaxy occurs.
8. The method of claim 1 , wherein forming the semi-insulating silicon carbide layer comprises:
supplying an impurity from a source, the impurity being selected from a group consisting of germanium and chromium.
9. The method of claim 1 , wherein the first semiconductor device is formed epitaxially.
10. The method of claim 1 , wherein the semi-insulating silicon carbide layer has a thickness and a leakage current, the leakage current varying as a function of the thickness and a voltage applied to the microelectronic device.
11. The method of claim 10 , wherein the leakage current varies as a function of V 2 /L 3 , where V= the voltage applied and L= the thickness of the semi-insulating silicon carbide layer.
12. The method of claim 11 , wherein the thickness is at least about 10 micrometers for the voltage of about 350 Volts.
13. The method of claim 1 , wherein the semi-insulating silicon carbide layer is formed such that the semi-insulating silicon carbide layer has much greater thermal conductivity than a silicon-dioxide layer.
14. The method of claim 1 , wherein the semi-insulating silicon carbide layer is formed such that the semi-insulating silicon carbide layer conducts more than 200 times as much heat as a silicon-dioxide layer per unit area.