Semiconductor structure having a unidirectional and a bidirectional device and method of manufacture
In various embodiments, semiconductor structures and methods to manufacture these structures are disclosed. In one embodiment, a method includes forming a portion of the unidirectional transistor and a portion of a bidirectional transistor in or over a semiconductor material simultaneously. Other embodiments are described and claimed.
1. A method of manufacturing a semiconductor device, the method comprising:
forming at least one recess in a semiconductor layer;
forming a unidirectional device in and over a first region of the semiconductor layer comprising the at least one recess, wherein the unidirectional device is disposed entirely within the recess to allow planarization of at least a portion of the first region, the unidirectional device comprising a higher voltage, asymmetric transistor having a source and a drain; and
forming a bidirectional device in and over a second region of the semiconductor layer, the bidirectional device comprising a lower voltage transistor.
2. The method of claim 1 , wherein:
forming the unidirectional device and forming the bidirectional device comprise:
simultaneously forming at least a portion of the unidirectional device and at least a portion of the bidirectional device.
3. The method of claim 1 , wherein the second region of the semiconductor layer is substantially devoid of the recess.
4. The method of claim 1 , further comprising:
providing a semiconductor substrate, wherein the semiconductor substrate comprises the semiconductor layer;
wherein said forming the unidirectional device further comprises forming at least a portion of a higher voltage device in the at least one recess; and
wherein said forming the bidirectional device further comprises forming at least a portion of a lower voltage device in the second region.
5. A semiconductor device, comprising:
a semiconductor layer having at least one recess formed therein;
a unidirectional device disposed in and over a first region of the semiconductor layer comprising the at least one recess, wherein the unidirectional device is disposed entirely within the recess to allow planarization of at least a portion of the first region, the unidirectional device comprising a higher voltage, asymmetric transistor having a source and a drain; and
a bidirectional device disposed in and over a second region of the semiconductor layer, the bidirectional device comprising a lower voltage transistor.
6. The semiconductor device of claim 5 , wherein:
at least a portion of the unidirectional device and at least a portion of the bidirectional device are formed simultaneously or nearly simultaneously.
7. The semiconductor device of claim 5 , wherein the second region of the semiconductor layer is substantially devoid of the recess.
8. The semiconductor device of claim 5 , further comprising:
a semiconductor substrate, wherein the semiconductor substrate comprises the semiconductor layer;
wherein the unidirectional device further comprises at least a portion of a higher voltage device disposed in the at least one recess; and
wherein the bidirectional device further comprises at least a portion of a lower voltage device disposed in the second region.