Semiconductor device including a deep contact and a method of manufacturing such a device
View Patent ↗A semiconductor device includes a buried layer and a deep contact for providing a low resistive connection to the buried layer. The deep contact is formed by doped polycrystalline silicon. A method of manufacturing a semiconductor device and a deep contact for providing a low resistive connection to the buried layer, with the steps of forming a buried layer, providing an active region adjacent the buried layer and forming a deep contact for providing a low resistive connection to the buried layer by patterning a contact shape for the deep contact on an upper surface of the active region, removing part of the active region underneath the contact shape to create a deep contact cavity. Subsequently a polycrystalline silicon layer for filling the deep contact cavity is deposited and doped.
1. A method of manufacturing a semiconductor device comprising the steps of:
forming a buried layer on a semiconductor substrate;
providing an active region adjacent the buried layer;
forming a deep contact for providing a low resistive connection to the buried layer by:
patterning a contact shape for the deep contact on an upper surface of the active region;
removing part of the active region underneath the contact shape to create a deep contact cavity; and subsequently
depositing a first polycrystalline silicon layer in the deep contact cavity;
doping the first polycrystalline silicon layer;
depositing a second polycrystalline silicon layer in the deep contact cavity; and
doping the second polycrystalline silicon layer.
2. The method of claim 1 , wherein the first polycrystalline silicon is in situ doped.
3. The method of claim 1 , wherein the first polycrystalline silicon layer is doped by first implanting dopant sources and then thermally distributing the dopant.
4. The method of claim 1 , wherein the step of removing part of the active region is stopped on top of the buried layer.
5. The method of claim 1 , wherein the step of removing part of the active region is stopped inside the buried layer.
6. The method of claim 1 , wherein the step of removing part of the active region is stopped under the buried layer.
7. The method of claim 1 , wherein the first layer of polycrystalline silicon further comprises germanium and/or carbon.