Phase change memory device, manufacturing method thereof and operating method thereof
View Patent ↗A phase change memory (PCM) device, a manufacturing technique of making the PCM device, and a way of operating the PCM device is presented. The PCM device is structured to have a silicon on insulator type substrate that provides an advantage of thermally insulating the active area of the PCM device without the need for an additional insulation layer. The PCM device has a phase change resistor PCR that has one terminal connected to a word line and the other terminal connected in common to the N-terminals of two PN diodes in which the P-terminals are connected in common to the bit line. As a result, a current flowing through the phase change resistor PCR is doubled which results in doubling the cell driving capacity.
1. A method of manufacturing a phase change memory device, the method comprising:
forming a first impurity region haying a N+ region in a semiconductor substrate;
forming a first insulating layer comprising a bottom electrode connected to the first impurity region over the semiconductor substrate;
forming a phase change layer which is connected to the bottom electrode and a top electrode over the first insulating layer;
forming a second impurity region having a P+ region in the first impurity region by using the top electrode as an ion-implanting mask; and
forming a bit line contact plug connected to the second impurity region,
wherein the first impurity region and the second impurity region are formed alternately in a same layer.
2. The manufacturing method according to claim 1 , wherein the semiconductor substrate has a SOI (Silicon On Insulator) structure comprising a first silicon layer, an insulating layer and a second silicon layer.
3. The manufacturing method according to claim 2 , wherein the first silicon layer comprises a N-type region.
4. The manufacturing method according to claim 1 , wherein forming the bottom electrode comprises:
forming the first insulating layer over the semiconductor substrate;
forming a contact hole which exposes the first impurity region by etching the first insulating layer; and
filling the contact hole with a conductive film to form the bottom electrode.
5. The manufacturing method according to claim 1 , wherein the top electrode is connected to a word line.
6. The manufacturing method according to claim 1 , wherein the first impurity region and the second impurity region comprise a PN diode.
7. The manufacturing method according to claim 1 , further comprising:
forming a bit line connected to the bit line contact plug.
8. The manufacturing method according to claim 7 , wherein forming the bit line contact plug comprises:
forming a second insulating layer over the resulting structure including the phase change layer and the top electrode;
forming a contact hole that exposes the second impurity region by etching the second insulating layer; and
filling the contact hole with a conductive film.