A method for producing a 3D memory device, the method including: providing a first level including a single crystal layer and first alignment marks; forming memory control circuits including first single crystal transistors, where the first single crystal transistors include portions of the single crystal layer; forming at least one second level above the first level; performing a first etch step including etching lithography windows within the at least one second level; performing a first lithographic step over the at least one second level aligned to the first alignment marks; and performing additional processing steps to form a plurality of first memory cells within the at last one second level, where each of the plurality of first memory cells include one of a plurality of second transistors, and where the plurality of second transistors are aligned to the first alignment marks with a less than 40 nm alignment error.

A semiconductor device, the device comprising: a plurality of transistors, wherein at least one of said plurality of transistors comprises a first single crystal source, channel, and drain, wherein at least one of said plurality of transistors comprises a second single crystal source, channel, and drain, wherein said second single crystal source, channel, and drain is disposed above said first single crystal source, channel, and drain, wherein at least one of said plurality of transistors comprises a third single crystal source, channel, and drain, wherein said third single crystal source, channel, and drain is disposed above said second single crystal source, channel, and drain, wherein at least one of said plurality of transistors comprises a fourth single crystal source, channel, and drain, and wherein said first single crystal channel is self-aligned to said second single crystal channel being processed following the same lithography step.

A transistor includes a semiconductor substrate, a first source/drain region and a second source/drain region in the semiconductor substrate with a channel region between the source/drain regions, and a gate over the channel region. In addition, the transistor includes a first phase transition material (PTM) region between the first source/drain region and the channel region, and a second PTM region between the second source/drain region and the channel region. The PTM regions provide the transistor with improved off-state current (I.sub.OFF) without affecting the on-state current (I.sub.ON), and thus an improved I.sub.ON/I.sub.OFF ratio. The transition threshold of PTM regions from dielectric to conductor can be customized based on, for example, PTM material type, doping therein, and/or strain therein.

A semiconductor device, the device including: a plurality of transistors, where at least one of the plurality of transistors includes a first single crystal source, channel, and drain, where at least one of the plurality of transistors includes a second single crystal source, channel, and drain, where the second single crystal source, channel, and drain is disposed above the first single crystal source, channel, and drain, where at least one of the plurality of transistors includes a third single crystal source, channel, and drain, where the third single crystal source, channel, and drain is disposed above the second single crystal source, channel, and drain, where at least one of the plurality of transistors includes a fourth single crystal source, channel, and drain, and where the first single crystal source or drain, and the second single crystal source or drain each include n+ doped regions.

A method for producing a 3D memory device, the method including: providing a first level including a single crystal layer and first alignment marks; forming memory control circuits including first single crystal transistors, where the first single crystal transistors include portions of the single crystal layer; forming at least one second level above the first level; performing a first etch step including etching lithography windows within the at least one second level; performing a first lithographic step over the at least one second level aligned to the first alignment marks; and performing additional processing steps to form a plurality of first memory cells within the at last one second level, where each of the plurality of first memory cells include one of a plurality of second transistors, and where the plurality of second transistors are aligned to the first alignment marks with a less than 40 nm alignment error.

A semiconductor device, the device comprising: a plurality of transistors, wherein at least one of said plurality of transistors comprises a first single crystal source, channel, and drain, wherein at least one of said plurality of transistors comprises a second single crystal source, channel, and drain, wherein said second single crystal source, channel, and drain is disposed above said first single crystal source, channel, and drain, wherein at least one of said plurality of transistors comprises a third single crystal source, channel, and drain, wherein said third single crystal source, channel, and drain is disposed above said second single crystal source, channel, and drain, wherein at least one of said plurality of transistors comprises a fourth single crystal source, channel, and drain, and wherein said third single crystal channel is self-aligned to said fourth single crystal channel being processed following the same lithography step.

A method for producing a 3D semiconductor device including: providing a first level, the first level including a first single crystal layer; forming first alignment marks and control circuits in and/or on the first level, where the control circuits include first single crystal transistors and at least two interconnection metal layers; forming at least one second level disposed above the control circuits; performing a first etch step into the second level; forming at least one third level disposed on top of the second level; performing additional processing steps to form first memory cells within the second level and second memory cells within the third level, where each of the first memory cells include at least one second transistor, where each of the second memory cells include at least one third transistor, and where the additional processing steps include depositing a gate electrode simultaneously for the second and third transistors.

A method for producing a 3D semiconductor device, the method comprising: providing a first level, said first level comprising a first single crystal layer; forming first alignment marks and control circuits in and/or on said first level, wherein said control circuits comprise first single crystal transistors, and wherein said control circuits comprise at least two interconnection metal layers; forming at least one second level disposed on top of said control circuits; performing a first etch step into said second level; and performing additional processing steps to form a plurality of first memory cells within said second level, wherein each of said memory cells comprise at least one second transistors, and wherein said additional processing steps comprise depositing a gate electrode for said second transistors.

A transistor includes a semiconductor substrate, a first source/drain region and a second source/drain region in the semiconductor substrate with a channel region between the source/drain regions, and a gate over the channel region. In addition, the transistor includes a first phase transition material (PTM) region between the first source/drain region and the channel region, and a second PTM region between the second source/drain region and the channel region. The PTM regions provide the transistor with improved off-state current (I.sub.OFF) without affecting the on-state current (I.sub.ON), and thus an improved I.sub.ON/I.sub.OFF ratio. The transition threshold of PTM regions from dielectric to conductor can be customized based on, for example, PTM material type, doping therein, and/or strain therein.

A method for producing a 3D semiconductor device, the method comprising: providing a first level, said first level comprising a first single crystal layer; forming first alignment marks and control circuits in and/or on said first level, wherein said control circuits comprise first single crystal transistors, and wherein said control circuits comprise at least two interconnection metal layers; forming at least one second level disposed on top of said control circuits; performing a first etch step into said second level; and performing additional processing steps to form a plurality of first memory cells within said second level, wherein each of said memory cells comprise at least one second transistors, and wherein said additional processing steps comprise depositing a gate electrode for said second transistors.