Word-line driver including pull-up resistor and pull-down transistor

1. An apparatus comprising:

a plurality of memory cells, each memory cell including a selector and a storage element coupled to the selector; and

a word-line driver including a pull-up resistor coupled to the selectors for the memory cells to access respective storage elements of the memory cells, wherein the pull-up resistor is a diffused resistance of a base of the selector.

2. The apparatus of claim 1 , wherein at least one selector of a memory cell coupled to the word-line comprises a pnp bipolar junction transistor.

3. The apparatus of claim 1 , wherein at least one storage element of a memory cell coupled to the word-line comprises a phase-change material.

4. The apparatus of claim 1 , further comprising an n-type metal-oxide-semiconductor (nMOS) transistor having a drain coupled to the pull-up resistor and the selectors of the memory cells coupled to the word-line.

5. The apparatus of claim 4 , wherein a gate of the nMOS transistor is configured to receive a select signal for accessing the respective storage elements of the memory cells coupled to the word-line.

6. The apparatus of claim 1 , further comprising a pull-down transistor coupled to the pull-up resistor and the selectors of the memory cells coupled to the word-line.

7. The apparatus of claim 6 , wherein the pull-down transistor comprises a pnp bipolar junction transistor having a base configured to receive a select signal to access the respective storage elements of the memory cells coupled to the word-line.

8. The apparatus of claim 1 , further comprising a memory array including the plurality memory cells and the word line, and another plurality of memory cells and another word line similarly constituted and coupled as the memory cells and the word line.

9. A method comprising:

forming a plurality of memory cells, each memory cell including a selector and a storage element coupled to the selector;

forming a word line coupled to the memory cells; and

forming a word-line driver including a pull-up resistor coupled to the word line and the selectors of the memory cells coupled to the word line, wherein the pull-up resistor is formed from a diffused resistance of a base of the selector.

10. The method of claim 9 , wherein the forming of the plurality of memory cells comprises:

forming the selectors of the memory cells by forming an array of vertical pnp bipolar junction transistors (BJT); and

forming the storage elements of the memory cells by forming a phase change material over emitters of the vertical pnp BJTs.

11. The method of claim 10 , wherein the array of vertical pnp BJTs includes a common base coupled to the pull-up resistor.

12. The method of claim 9 , wherein the forming of the word-line driver includes forming the pull-up resistor in the common base.

13. A system comprising:

a memory device including:

a plurality of memory cells, each memory cell including a selector and a storage element constituted with phase change material and coupled to the selector; and

a plurality of word lines coupled to selectors of corresponding subsets of the memory cells, each word line having a word-line driver including a pull-up resistor coupled to the selectors of the corresponding subset of memory cells to access respective storage elements of the corresponding subset of memory cells, wherein the pull-up resistor is a diffused resistance of a base of the selectors;

a host logic device bus; and

a bus interface unit operatively coupled between the memory device and the host logic device bus.

14. The system of claim 13 , wherein the memory device and the bus interface unit form an embedded memory module.

15. The system of claim 13 , wherein the system is a selected one of a desktop or laptop computer, a server, a set-top box, a digital reorder, a game console, a personal digital assistant, a mobile phone, a digital media player, or a digital camera.