High electron mobility transistor
AssigneeCree, Inc.
InventorAdam William Saxler
Life of this patent
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Abstract
A HEMT device including a GaN channel structure including a very thin (Al,In,Ga)N subchannel layer that is disposed between a first GaN channel layer and a second GaN channel layer, to effect band bending induced from the piezoelectric and spontaneous charges associated with the (Al,In,Ga)N subchannel layer. This GaN channel/(Al,In,Ga)N subchannel arrangement effectively disperses the 2DEG throughout the channel of the device, thereby rendering the device more linear in character (relative to a corresponding device lacking the subchannel (Al,In,Ga)N sub-layer), without substantial loss of electron mobility.
Claims56
A HEMT device comprising:
- at least four layers comprising (Al, In, Ga)N materials, said four layers defining three heterojunctions disposed in sufficient proximity to generate a charge density profile as a function of depth having two local maxima and a nonzero local minimum disposed between the two local maxima;
- wherein each heterojunction comprises an interface between (Al, In, Ga)N materials sufficiently different in bandgap character that a two-dimensional electron gas is formable therebetween;
- and
- wherein the local minimum corresponds to an intermediate (Al, In, Ga)N subchannel layer of said at least four layers, said subchannel having a thickness not exceeding 75 Angstroms and being disposed between two channel layers of said at least four layers corresponding to said two local maxima.
A FET device comprising:
- at least four layers comprising (Al, In, Ga)N materials, said four layers defining three heterojunctions disposed in sufficient proximity to generate a charge density profile as a function of depth having two local makinla and a nonzero local minimum disposed between the two local maxima;
- wherein each heterojunction comprises an interface between (Al, In, Ga)N materials sufficiently different in bandgap character that a two-dimensional electron gas is formable therebetween;
- and
- wherein the local minimum corresponds to an intermediate (Al, In, Ga)N subchannel layer of said at least four layers, said subchannel having a thickness not exceeding 75 Angstroms and being disposed between two channel layers of said at least four layers corresponding to said two local maxima.
A method of improving linearity without substantial loss of mobility in a HEMT device, comprising fabricating the HEMT device with at least four layers comprising (Al, In, Ga)N materials, said four layers defining three heterojunctions disposed in sufficient proximity to generate a charge density profile as a function of depth having two local maxima and a nonzero local minimum disposed between the two local maxima;
- wherein each heteroj unction comprises an interface between (Al, In, Ga)N materials sufficiently different in bandgap character that a two-dimensional electron gas is formable therebetween;
- and
- wherein the local minimum corresponds to an intermediate (Al, In, Ga)N subchannel layer of said at least four layers, said subchannel having a thickness not exceeding 75 Arigatroms and being disposed between two channel layers of said at least four layers corresponding to said two local maxima.
Dependencies are inferred from the claim text.